When I click on messages there is no edit option on my 6s phone

The EDIT option is only available in iOS 16. You have an iPhone 6s and it can only be updated up to iOS 15.7. Your iPhone 6s, therefore, does not have the Edit option in the Messages app.

Axel F.

You were told that there is an edit option in iOS 16. You may have confused that with your iPhone 6, which can only be updated to iOS 12.5.6.