How to enable my MMS massage on iphone 6?

Enter the setttings app and scroll down until you reach the messages row circled in yellow in the screenshot below...

Make sure the yelllow circled mms messages option is enabled like below...

Cheers!

you can visit this link :

https://www.wikihow.tech/Enable-MMS-Messaging-for-iPhone

You must be enrolled in a data plan that supports MMS in order to use it.