Where is sent box on iPhone 7 I have a gmail account

Hi

Go to settings down to Email Accounts delete account that not working correctly then add account back again.

Later go to i books download ios 11 user guide &iPhone 7 guide both are free.

Cheers

Brian 🇬-1F1E7;

When you tab on Mail there should be a list of Mailboxes.

Then there should be listing for GMAIL and all the folder, including Sent, should be there.