The fastest way to attach a file in Outlook

To attach a file in Outlook, click the Attach button in the message compose window, then select the file from your computer. The button location depends on which version of Outlook you use — in the web version and newer desktop versions, it's a paperclip icon in the toolbar. In older desktop versions, it's labeled "Attach File" in the Insert menu. Once you select a file, it appears as an attachment line in your message, and you can send the email normally.

You can also drag a file directly from your computer into the message body or attachment area, which works in all versions. Most versions let you attach multiple files at once by holding Ctrl (or Cmd on Mac) while selecting files, then clicking Open.

Key Takeaways

  • Click the paperclip icon or Attach button in the compose window, then select your file from your computer.
  • Dragging a file directly into the message body works as an alternative method in all Outlook versions.
  • You can attach multiple files by selecting them together before clicking Open, or by attaching them one at a time.
  • File size limits vary by account type — Outlook.com allows up to 20 MB per file, while Exchange accounts may have different limits set by your organization.
  • If an attachment fails to send, check the file size and your internet connection, then try again or use OneDrive to share the file instead.

Where to find the Attach button in different Outlook versions

In Outlook on the web (Outlook.com and Microsoft 365 web), the paperclip icon appears in the toolbar above the message body. Click it once, and a file browser opens so you can navigate to your file. The button stays visible as long as the compose window is open.

In Outlook desktop for Windows and Mac (versions 2019 and newer), the paperclip icon is also in the toolbar at the top of the compose window. If you use an older desktop version, go to the Insert menu instead and select Attach File.

In Outlook mobile apps (iPhone and Android), tap the paperclip or plus icon at the bottom of the compose screen. This opens your phone's file browser, where you can select a photo, document, or other file from your device.

Attaching files by dragging and dropping

Dragging a file directly into Outlook is often faster than using the Attach button. Open your file manager or desktop, locate the file you want to send, and drag it into the message compose window. Most versions of Outlook accept files dropped into the message body or into a designated attachment area.

This method works in Outlook on the web, desktop versions, and some mobile apps. If dragging doesn't work in your version, use the Attach button instead — the result is the same.

Attaching multiple files at once

To attach several files in one action, open the file browser (by clicking Attach), then hold Ctrl on Windows or Cmd on Mac while clicking each file you want. Once you've selected all of them, click Open or Insert, and they all attach to the message at once.

If your file browser doesn't support multi-select, or if the files are in different folders, attach them one at a time by clicking Attach again after the first file uploads. There's no limit to how many files you can attach, but the total size of all attachments is limited by your account.

File size limits and what to do if a file is too large

Outlook.com and Microsoft 365 web accounts allow up to 20 MB per individual file. Exchange accounts used by organizations may have different limits — check with your IT department or email administrator if you're unsure. If a file exceeds the limit, Outlook usually warns you before you send.

If a file is too large, you have two options. First, compress the file by right-clicking it, selecting Send to, and choosing Compressed (zipped) folder on Windows, or using the Archive utility on Mac. Second, upload the file to OneDrive or SharePoint, then share the link in your email instead of attaching the file itself. This method works for files of any size and lets recipients read the file on their own schedule.

Troubleshooting attachments that won't send

If an attachment fails to send, the most common causes are file size, internet connection, or a temporary server issue. Check that the file size is under your account's limit, make sure you're connected to the internet, and try sending again. If the problem persists, close the compose window, wait a few minutes, and start a new message.

If a specific file consistently fails to attach, try compressing it or uploading it to OneDrive and sharing the link instead. You can also try attaching a different file to confirm the problem is with that particular file and not your Outlook account. Contact your email provider or IT department if attachments fail across multiple messages.

Viewing and removing attachments before you send

Before you send a message, review the attachment list to make sure you attached the right file. In Outlook on the web and desktop, the attachment appears as a line item in the compose window showing the filename and file size. Click the X next to any attachment to remove it.

On mobile, swipe left on the attachment (iPhone) or long-press it (Android) to delete it. If you accidentally send a message with the wrong attachment, you can recall it in Outlook desktop and some Microsoft 365 accounts — go to the Sent folder, open the message, and select Actions > Recall This Message. Recall doesn't always work if the recipient has already opened the message, so it's better to catch the mistake before sending.

Frequently Asked Questions

Can I attach a file from OneDrive or SharePoint instead of uploading from my computer?

Yes. In Outlook on the web and desktop, click the Attach button and look for an option to browse OneDrive or SharePoint. Select the file from your cloud storage, and Outlook inserts a link to it in the message. This is useful for large files or when you want recipients to always see the latest version.

What happens if I attach a file and then edit it on my computer?

If you attached a copy of the file, changes you make afterward won't appear in the email the recipient receives — they get the version from the moment you sent it. If you attached a OneDrive link instead, the recipient sees the current version of the file, including any edits you make later.

Why does Outlook say my attachment is blocked?

Some file types are blocked by default for security reasons, including .exe, .bat, and certain other executable files. If your organization uses Exchange, your IT department may have blocked additional file types. Ask your IT team to unblock the file type, or compress the file and send it as a .zip instead.

Can I attach a file from my phone's camera roll or photos app?

Yes. In Outlook mobile, tap the attachment icon and select Photos or Files to browse your phone's storage. Select the photo or file you want, and it attaches to the message. You can attach multiple photos by selecting them together before confirming.