1. Mail app- Click on your Mail app and click Preferences from the drop down menu.
2. Accounts- From the Preferences menu, click on Accounts, then click on iCloud account (make sure you’re signed in to it), and then click on Advanced.
3. Advanced settings- Under the Advanced Settings menu, you will see a list of options, including one that says “Send large attachments with Mail Drop” and a checkbox next to it. Click to add a checkmark to the box if it is not already present.
4. Composing and attaching- Compose your email and add the large attachment. Note: If the recipient is an iCloud user, they will receive the file seamlessly, as if it were a normal attachment. If they are not, they will receive a link to download the attachment for viewing.