How can a member edit their own personal information?
As an administrator, you'll need to go to Configuration > General Settings. go to the Features tab and look towards the bottom. You'll see member options here.
The first two choices, 'Allow members to log in and edit contact information,' and 'Allow logged in members to add new family members' will need to be checked.
As a member, first log in to the site. You'll see an option at the bottom of the right hand menu, 'Edit My Account.' Click that, and you can add family members. If you click on a member name here, you'll be able to update member contact information.