To add or edit a phone number for a resident you will want to go to My Dashboard > Resident Management. You can even add international numbers!
First, select the residents name from the User Lookup results so that their information appears on the right under Contact info.
To change the phone number, click into the phone number box. Notice, you can also change the country for international numbers on the left of the phone number box by selecting the flag drop down on the right.
To save changes click Ok.