I'm getting the iphone 7 tomorrow & i currently have the 6 how am i able to transfer content from old phone to my new one?

I'm trading my current phone in when buying the new one.

They userly have a machine where you plug in both phones and they transfer everything

Establish a backup and then restore it on the new phone.

Take the 6. Backup everything to your iCloud account. Delete (wipe completely) everything from your phone before trading it in. When you first open the 7 it will ask if you want to set up from a previous backup. Say yes, then download the one you made on the 6.