Multiple email accounts

Or only shows email from 2 or more email accounts and not just all.

 

I have four accounts on my phone but I only receive one on my watch. Open the watch app on the phone. Go to mail, turn off the accounts you don't want.

 

In the Watch App, My Watch, Mail, Include Mail option can only select one mailbox at a time. No option to choose 2 or 3 of the four available, just All Inboxes, or one other inbox, not multiple.

Note this is where you can turn off notification per mailbox though