Primary accountholders between ages 18 and 26 will need to bring their social security number and a government-issued ID. If the primary accountholder is under 18, the joint owner of the account willneed the child’s social security number and an identification card, driver’s license or passport, if they have one. As a co-owner, you’ll need your social security number and an ID, also. Remember, only Cash Accounts and Stash Accounts can be opened online. Rookie Accounts must be opened in branch, due to federal regulations.