VoLTE stands for Voice Over LTE, which is a requirement for all the major carriers as 3G is phased out.

If that link ( https://www.amazon.com/gp/product/B08DDHKLVN) is the exact variant of the Galaxy A01 model you have, then you have an international model, which is not usually a good idea to use in the USA. I don't believe it will utilize band 71 for one thing. And whether or not it is VoLTE capable, I have no clue.

There are several models of the A01. You should find out which you have and then look up the specs on these sites https://www.phonemore.com/specs/?q=Galaxy%20A01 https://www.gsmarena.com/res.php3?sSearch=Galaxy+A01

This link on Tello may also help you with info you need to know about phone choice for T-mobile network. https://tello.com/help_center Go there and do a search for "band 71" and read the resulting FAQ.

You should also use IMEI checkers, but never rely on them 100% https://tello.com/bring_your_own_phone

Sorry, whats voLTE?

I searched on my smartphone's Amazon page but voLTE is not mentioned. However, T-Mobile is: Galaxy A01 : https://www.amazon.com/gp/product/B08DDHKLVN/ref=ppx\_yo\_dt\_b\_search\_asin\_title?ie=UTF8&psc=1