Hi, Katie!
Welcome to the Disney Parks Moms Panel! Don't you love being an
Annual Passholder?! It's truly the most magical club on earth. I have especially enjoyed the extra pixie-dusted benefits in honor of Walt Disney World® Resort's 45th anniversary!
Great news, you will not need to provide any documentation for your child's annual pass! All you need to do is set up a guest profile for her on your My Disney Experience Account. Once she has a profile, you can than purchase the pass and "assign" it to her at checkout. It will then be auto-magically linked to her on her account (which you manage, of course) and an Annual Passholder MagicBand will be shipped as soon as you complete the customization process. However, if she has a MagicBand that is linked to her and still active from a previous visit, that MagicBand will also contain her Annual Pass information.
Also, her 12 months of magic, or "activation date" will not start until she enters a theme park through a touchpoint, not when you purchase her pass.
I hope this is helpful, Katie! And let me be the first to congratulate your little princess on reaching another Disney milestone, becoming an "AP."
Faith