A document is any file you create and save on your computer
A document is a file that holds information you want to keep — text, numbers, images, or a mix of all three. When you write something in Microsoft Word, create a spreadsheet in Excel, or save a photo from your camera, you are creating a document. Your computer stores it as a file with a name and a location, usually in a folder you can find and open later.
Documents are different from programs. A program is software that does something — Word lets you write, Excel lets you calculate, Chrome lets you browse the web. A document is what you make with that program. The document sits on your hard drive or in cloud storage, waiting for you to open it again.
Every document has a file type, shown by the letters after the dot in its name. A Word document ends in .docx. A photo ends in .jpg or .png. A spreadsheet ends in .xlsx. These letters tell your computer which program should open the file when you double-click it.
Key Takeaways
- A document is any file you create and save — a letter, a photo, a spreadsheet, a video — stored on your computer or in the cloud.
- The file type (the letters after the dot in the name) tells your computer which program should open it.
- You can organize documents into folders, rename them, move them between locations, and back them up to protect them from loss.
- Cloud storage like Google Drive or OneDrive lets you access your documents from any device and share them with other people.
Where documents live on your computer
Documents are stored in folders, which are like drawers in a filing cabinet. Your computer comes with a default location called Documents, usually found in your user folder. You can create new folders inside Documents to organize your files — one for taxes, one for recipes, one for work projects.
When you save a document for the first time, your computer asks you where to put it and what to name it. You choose the folder and type a name. From then on, that document stays in that location until you move it or delete it. You can see all your documents by opening File Explorer (on Windows) or Finder (on Mac) and navigating to the folder where you saved them.
Some documents are hidden by default. Your computer stores settings and temporary files in folders you do not normally see. You do not need to touch these — they are for the system to use. The documents you create and care about stay in the folders you choose.
File types and which program opens them
The file type is the key to understanding which program your computer will use. When you save a letter in Word, it becomes a .docx file. When you save the same letter in Google Docs, it becomes a .gdoc file. Both are documents, but they use different formats and open in different programs.
Common document file types include .docx (Word), .xlsx (Excel), .pdf (any program that reads PDFs), .txt (plain text, opens in Notepad), .jpg and .png (images), and .mp4 (video). If you try to open a file and the wrong program opens, you can right-click the file, choose "Open with", and pick a different program from the list.
Some file types are universal, meaning many programs can open them. A .pdf file opens in Adobe Reader, but also in Chrome, Edge, and most other browsers. A .txt file opens in Notepad, but also in Word, Google Docs, and dozens of other programs. Other file types are proprietary — a .docx file is designed for Word, though Google Docs and other programs can open it too.
Saving, naming, and organizing documents
When you create something new in a program, it exists only in your computer's memory until you save it. If the power goes out or the program crashes before you save, your work is gone. Saving writes the document to your hard drive so it stays there even after you close the program.
Give your documents clear names so you can find them later. "Taxes 2024" is better than "Document1". "Resume March 2024" is better than "Resume". Avoid special characters like / or \ in the name — they can confuse your computer. Use spaces, hyphens, or underscores instead.
Organize documents into folders by project, by year, or by topic — whatever makes sense for how you work. You can create folders inside folders. A folder structure might look like: Documents > Taxes > 2024 > Federal Return. This way, when you need a file six months from now, you know exactly where to look.
Cloud storage and accessing documents anywhere
Cloud storage means your documents live on a company's servers on the internet, not just on your computer. Services like Google Drive, Microsoft OneDrive, and Dropbox let you upload documents and access them from any device — your phone, tablet, or a different computer. You log in with your username and password, and your files are there.
Cloud storage also makes sharing easier. Instead of emailing a file back and forth, you can give another person a link to the document. They can view it, edit it, or read it depending on the permissions you set. Multiple people can work on the same document at the same time, and everyone sees the changes when ready.
Most cloud services offer free storage up to a limit — usually 15 to 100 gigabytes depending on the service. If you need more, you pay a monthly fee. Cloud storage also backs up your documents automatically, so if your computer breaks, your files are still safe on the internet.
Backing up documents so you do not lose them
A backup is a copy of your documents stored somewhere else. If your hard drive fails, a virus deletes your files, or your computer is stolen, a backup means you still have your work. There are three main ways to back up: cloud storage, an external hard drive, or both.
Cloud storage backs up automatically — as soon as you save a document to Google Drive or OneDrive, it is backed up. An external hard drive is a portable storage device you plug into your computer. You can copy your Documents folder to it once a week or once a month. Some people use both: cloud storage for daily work and an external drive as a second backup for important files.
Do not rely on only one backup method. If your only backup is an external drive and that drive breaks, you have lost everything. If your only backup is cloud storage and your account gets hacked, your files could be compromised. A good backup plan uses at least two different methods.
What happens when you delete a document
When you delete a document, it usually goes to the Recycle Bin (on Windows) or Trash (on Mac). It is not gone yet — it is just hidden. You can open the Recycle Bin or Trash, find the file, and restore it. This gives you a safety window if you delete something by accident.
If you empty the Recycle Bin or Trash, the document is harder to recover, but recovery software can sometimes find it. If you want to permanently delete a sensitive document so no one can recover it, use a find deletion tool that overwrites the file with random data. For most everyday documents, emptying the Recycle Bin is enough.
Frequently Asked Questions
What is the difference between a document and a file?
A document is a type of file — specifically, a file that holds information you created or saved. A file is a broader term that includes programs, system files, and anything else your computer stores. All documents are files, but not all files are documents.
Can I open a document on a different computer?
Yes, if you have the right program installed. A .docx file opens on any computer with Word, Google Docs, or compatible software. If you email the file to yourself or store it in cloud storage, you can read it and open it on another computer. Some file types are more universal than others — a .pdf opens almost anywhere, while a specialized file type might need specific software.
What does it mean when a document is "read-only"?
A read-only document is one you can open and view, but not edit or save changes to. This usually happens when someone shares a document with you but does not want you to change it, or when a file is on a write-protected drive. You can still make changes on your screen, but when you try to save, the computer will not let you. You can save a copy with a new name if you want to edit it.
How much space do documents take up on my computer?
It depends on the type. A text document with a few pages is usually less than 1 megabyte. A photo is typically 2 to 5 megabytes. A video can be hundreds of megabytes or several gigabytes. You can right-click a file and choose Properties to see its exact size. If your computer is running low on storage, deleting old documents or moving them to cloud storage or an external drive frees up space.
What is the difference between saving and exporting a document?
Saving keeps a document in its original format — a Word document stays a .docx file. Exporting converts it to a different format — you might export a Word document as a .pdf so anyone can view it without Word installed. Exporting is useful when you need to share a document with someone who uses different software or when you want a format that is harder to edit.