Hey there! Are you referring to something like a widget? What kind of phone do you have? If it's an Android, you can view your options by long pressing on the screen and selecting Widgets. You should see one there for Visual Voicemail. Tap to select then long press the icon and drag it to your desired location on the screen.
The solution was to install the correct T.mobile voice mail icon on my phone's desktop.
Manage your T-Mobile account