Esim

Yes, you can convert your sim to an esim. You can do that right from your phone in settings. A Verizon sim will work if your phone is unlocked and ATT can not lock your phone if it’s already unlocked.

Thanks for quick reply . I tried to convert my physical Sim into eSim. It stuck and got error to call ATT. 

I called att and they said I should visit ATT store. Att will lock my Unlocked iPhone for 6 month and I cant use any other Carrier Sim. Is that true then Dual Sim Support on Unlocked Device for USA is just garbage. 

Att will lock my Unlocked iPhone for 6 month and I cant use any other Carrier Sim.

That is not true. Whoever is telling you that is clueless. Once again, ATT can not lock an already unlocked phone.

Were you connected to Wi-Fi when trying to convert the SIM to eSIM?  Needs connection to do the conversion. 

Yes I was connected with WiFi 

I am attaching Screenshots I am using Prepaid Service from ATT 

My issue got resolved. One of Prepaid Tech Support Girl was able to fix my issue without visiting ATT store and She activated my Prepaid Sim by EID of my Phone. Now I can use eSim from ATT and Physical Sim from Verizon .

Thanks for all those who replied to my chat . I really appreciate .