You can activate your AT&T SIM in-store, online, or by contacting customer service. The process is similar for postpaid and AT&T prepaid customers.

How to activate DND service on your Airtel prepaid and postpaid Number 1. Open your phone’s default messaging app. 2. Type ...

consider a trade-in and upgrade to a T-Mobile phone or tablet. Youll need a number transfer PIN for this You may find it ...