Would an AT&T Go sim card fit/work in a regular AT&T phone?

I need a sim card for my AT&T iPhone 6s and I found an AT&T Go sim card in Walmart and I would like to know if I can use this for a regular AT&T iPhone.

Appreciate it!

Yes

It won't work with postpaid service, only the prepaid

It should, as long as it's the correct form factor. My husband was able to switch his Samsung Galaxy from ATT to ATT Go without any problems.

No

As long as its a nanoSIM it should fit fine. Should also work fine.

Sure you can, just make sure the SIM is nano-SIM.

It will but why not just go into the att store and ask them for a regular sim card? With the prepaid simes it will be locked to the phone it was activated on for 6 months. That means you can't swap it between phones. At&t of course will change them out before 6 mounth if you ask them to though. The regular sim cards are unlocked from the get go. You can use them in another phone when you want to. You can also put the prepaid service on at the time you're in the store.