The Telstra 24x7 app is just for Telstra users. It allows you to access some of every day functions that you may use via their website and/or your online account. The app is more user-friendly than the web browser account because the app has fewer functions and less to deal with. The changes you may make to your account with the app are limited, the app is just for checking up on your account and recharging your prepaid account.
A quick-access app for Telstra customers
Download the Telstra 24x7 app and enter your account. Input your details and click the register button. Once you have registered, you will be able to see your current bills and previous bill summaries. You may pay your bills and see estimates for your current usage. If you use pre-paid services, then you may check your current balance and you may recharge your service. The app has basic visualizations that allow you to see things such as how much data you have left, or how much time is left on your account before your data expires. You may also see recent charges highlighted in large blue letters and numbers.
Okay if you can get it to work
The Telstra 24x7 app seems to be very choosey about which devices it will work on and which it will not. Most of the negative online reviews about the app are focused on how the app crashes or how it will not work. If the app doesn't work for you, then forget it and continue accessing your account via your web browser. If it does work, then it takes away the hassle of having to log in via your web browser to see your account.