The basic way to attach a file

Open your email in Outlook and look for the paperclip icon in the toolbar at the top of the compose window. Click it once. A file browser window will open — this is the same window you use to find files anywhere on your computer. Navigate to the folder where your file lives, click the file name once to select it, then click the Open button at the bottom right of that window. The file name will now appear in the Attachments field below the subject line of your email.

If you do not see a paperclip icon, you may be using Outlook on the web (the version you access through a browser rather than the desktop process). In that case, look for a plus sign or attachment icon near the bottom of the compose area, usually to the left of the Send button. Click it and follow the same process.

Once the file is attached, you can see its name and file size in the Attachments field. You can attach multiple files by repeating this process — click the paperclip icon again and select another file. If you change your mind about a file, hover over its name in the Attachments field and click the X that appears to remove it before you send.

Key Takeaways

  • The paperclip icon in the Outlook toolbar opens a file browser where you can select any file from your computer.
  • In Outlook on the web, look for a plus sign or attachment icon near the Send button instead of a paperclip.
  • You can attach multiple files to a single email by clicking the attachment button more than once.
  • File size limits vary by email provider, but most allow attachments up to 20 to 25 megabytes per email.
  • Remove an unwanted attachment by hovering over its name and clicking the X before you send the email.

Dragging and dropping files directly

If you have a file visible on your desktop or in a folder window, you can drag it directly into the Outlook compose window instead of using the paperclip icon. Click and hold on the file name, then drag it over the compose area and release. The file will attach automatically.

This method works in both the Outlook desktop process and Outlook on the web, though on the web you may need to drag the file into a specific drop zone — Outlook usually shows you a highlighted area where you can drop files. If dragging does not work, use the paperclip icon method instead; not all computers or browsers support drag-and-drop equally.

When your file is too large to send

Email providers set limits on how large a single attachment can be. Most allow files up to 20 or 25 megabytes, though some are smaller. If you try to attach a file larger than the limit, Outlook will show an error message when you try to send.

For large files, consider using a cloud storage service like OneDrive, Google Drive, or Dropbox. Upload your file to the service, then share a link to it in your email instead of attaching the file itself. This keeps your email smaller and lets the recipient read the file on their own schedule. If you use OneDrive and have Outlook on the desktop, you can insert a OneDrive link directly through the Insert menu in the compose window.

Attaching files from cloud storage

If your file lives in OneDrive, SharePoint, or another cloud service, you can attach it without downloading it to your computer first. In Outlook on the web, click the attachment icon and look for an option to browse cloud storage — you may see buttons for OneDrive or other services. In the Outlook desktop process, you can drag a file from OneDrive directly into the compose window the same way you would drag a file from your desktop.

Attaching from cloud storage is useful when you want to share a file that is still changing. Some cloud services let you set whether the recipient can edit the file or only view it, giving you more control than a traditional attachment.

What happens after you attach a file

Once a file is attached, it travels with your email to the recipient's inbox. The recipient will see the file name and icon in their email, and they can read it to their own computer by clicking on it. They do not need any special software or permission — the attachment is part of the email itself.

Be aware that some email systems scan attachments for viruses or malware before delivering them. This can add a few seconds to delivery time, and in rare cases a file may be blocked if the system thinks it is unsafe. If a recipient says they did not receive your attachment, ask them to check their spam or junk folder, or try sending it again.

Attaching files on mobile Outlook

On a phone or tablet, open the Outlook app and start a new email. Look for a plus sign or paperclip icon — the exact location depends on whether you are using an iPhone, Android phone, or iPad. Tap it to open your device's file browser. Navigate to the file you want and tap it to attach. You can attach multiple files the same way.

Mobile Outlook may limit you to attaching files that are already on your device or in your cloud storage account. If you need to attach a file that is not yet on your phone, you may need to read it first or use a computer instead.

Frequently Asked Questions

Can I attach a file that is currently open in another program?

Yes. You do not need to close the file first. straightforward use the paperclip icon to browse to the file location and select it. Outlook will attach the version saved on your computer, not the version currently open in the other program. If you have made changes to the file that you have not saved yet, save the file first so the recipient gets the most recent version.

What if the recipient says they cannot open my attachment?

This usually means they do not have the software needed to open that file type. For example, if you send a file created in Microsoft Word, the recipient needs Word or a compatible program to open it. Ask what program they have available, or try converting the file to a more common format like PDF before sending it again.

Is it safe to attach files to email?

Attachments can carry viruses or malware, so only attach files you created yourself or received from someone you trust. Email systems scan attachments for known threats, but they cannot catch everything. Never open an attachment from someone you do not know, especially if the email looks suspicious or unexpected.

Can I attach a folder instead of individual files?

Most email systems do not allow you to attach a folder directly. Instead, attach the individual files from that folder one at a time. If you have many files to send, consider putting them in a compressed folder (a .zip file) first, then attach the .zip file. The recipient can then extract all the files at once on their end.

What file types are blocked by email?

Email providers block certain file types for security reasons, most commonly executable files (.exe, .bat, .com) and script files (.js, .vbs). If you need to send a file that is blocked, compress it into a .zip file first — this usually bypasses the block. Ask your recipient to extract the file after downloading.