I need my trash button to appear so I can delete emails

What kind of account it is? iCloud, gmail?

For Gmail, this is how you do it.. Probably similar for others. iCloud mail is a bit different.

Go to Settings > Mail > Accounts > Gmail > Account > Advanced and under 'Move Discarded Messages into:', select Deleted Mailbox. Then navigate back to Account and press Done

no problem, glad to be of help!