In the Vertical 3-dot menu in compose mode you have the following options:
- Attach a File – Send an attachment by selecting which file you wish to send
- Take a Picture – Send a new picture as an attachment
- Add Cc/Bcc – Send a copy of the email to others
- Set High Priority – Let your recipients know the email is important
- Enable Read Receipt – If your provider allows, receive an email once the recipient has read your email
- Enable Plain Text Only – Send an email using only plain text