Use Mail extensions in Mail on Mac
Apps you download from the App Store can include different types of Mail extensions to help you send and receive email messages using the Mail app on your Mac. You can manage Mail extensions—turn them on or off, or uninstall them—in Mail preferences.
Types of Mail extensions
Apps can provide compose, action, content blocker, or security extensions for Mail.
Compose extensions can help you write messages. For example, validate recipients’ email addresses as you enter them, or add headers to certain messages. If an extension’s icon isn’t available in the Compose window toolbar, you can customize the toolbar to add it.
Action extensions can help you manage your inbox. For example, flag certain messages or move them to another mailbox, such as the Junk or Archive mailbox. If an extension performed an action on a message, the Extension icon
is shown in the message header.Content blocker extensions can help protect your privacy. For example, prevent remote content (such as images) from being loaded when you read messages and used to let senders learn your Mail activity.
Security extensions can help you encrypt, decrypt, and sign messages. If an extension has the information it needs to encrypt or sign a message you’re writing, an encrypted icon (a closed lock) or a signed icon (a checkmark) appears in the message header.
After an extension is installed, you must turn it on in Extensions preferences in Mail before you can use it.
Manage Mail extensions
In the Mail app
on your Mac, choose Mail > Preferences, then click Extensions.In the list of Mail extensions available on your Mac, do any of the following:
Turn an extension on or off: Select or deselect the extension’s checkbox.
Remove an extension: Select the extension, then click Uninstall. Or delete the app that contains the extension.
Uninstalling extensions, and turning them on or off, takes effect immediately.
Use a Mail extension
In the Mail app
on your Mac, click an extension’s icon in the toolbar of the Mail viewer or Compose window, then follow the onscreen instructions.If the extension doesn’t seem to be working, make sure you turned it on in Extensions preferences in Mail. If an extension’s icon isn’t available in the toolbar, you can customize the toolbar to add it.
If the Extension icon is shown in a message header, an extension you’re using took an action on that message.