My Viettel: Đăng Ký 4G5G is an Android application developed by ViettelData. It is a free lifestyle app that aims to help Viettel customers easily find and subscribe to the right data packages according to their needs. With this app, users can easily subscribe to monthly, daily, yearly, or purpose-specific data packages such as game packages or packages for accessing social media platforms like Facebook, Zalo, Youtube, and Tik Tok.

The main features of the app include checking promotional packages based on the user's mobile number, subscribing to Viettel data packages, subscribing to combo packages for both data and voice calls, subscribing to messaging and calling packages for internal network usage, subscribing to short-term data packages, and subscribing to purpose-specific data packages. The app also provides additional utilities such as checking remaining data volume, connecting to customer care, registering for wired internet installation, and updating SIM card information.