To set up the application on your iPhone, first, open the Phone application on your iPhone. Next, tap the Voicemail tab and then tap on Set Up now. If you already have an existing account, please enter its credential. However, if you do not, please set up a voicemail password that you will remember and then tap on done. On the AT&T visual voicemail app. Select Custom or Default; you can record a new greeting if you choose custom. Lastly, select Save.
Visit: https://contactforhelp.com/att/