Can I use the IPhones hotspot?

My Internet connection has been down for two days and I have AT&T well at least I did my dad canceled and were getting Comcast. In the meantime I wanted to use the personal hotspot option on th iPhone. I still have AT&T as a phone service provider. They want me to sign in using my AT&T username and password. My dad said he canceled. Do I have to have Internet service with AT&T to use hotspot or can I just have phone service with mobile Internet.

When you use Hotspot, it doesn't give you Wi-Fi, it gives other people Wi-Fi that your phone is creating