You add your gmail account to Apple Mail because you like Apple Mail. Everything looks good, and you can send and receive messages as expected. Now you get a difficult question from a client and you want to see the email you sent to them from your iPhone 2 days ago. Naturally, you click on ‘Sent’ folder, and scroll down… Oops! The email you sent from your iPhone is missing from your Macs Sent folder.
Luckily, this is easy to fix. First you need to search for the proper Gmail sent messages folder which shows ALL sent messages, not just ones sent from your Mac. You can find it if you dig into EMAIL ACCOUNT NAME -> Sent Messages . Now simply right click on this folder and choose the menu option Mailbox -> Use This Mailbox For -> Sent.