can i user t mobile sim card from a contract on a prepaid phone?

[Banaki I]

my grandmother phone broke shes old she just needs a simple phone that dials and n holds address book but t mobile has complicated phone for her age or want her to extend contract. i was looking at prepaid t mobile phone and they are simple and good for her. i was wondering if i can use the simcard from her contract phone and install it on a simple prepaid phone? can we use the prepaid phone like normal