From the Visual Voicemail inbox, tap a message to open it.
Tap and hold the voicemail sender's name.
Tap the Edit icon (located in the upper-right).
Edit any of the information (e.g. name, phone, address, email, etc.) then tap Save (located in the upper-right).
Depending upon the account type, the options presented may vary.
To add a pause (a 2-second delay between numbers) or wait, tap *#, tap Pause (,) or Wait (;) then tap Save.
To change the type of a selection (e.g., Phone, Address, Date, etc.) tap the Dropdown menu located directly beneath the selection then select the desired choice (e.g., Mobile, Work, Birthday, etc.).