Great question! I recently just did this myself the other day for the very first time! :-)
Will you be doing this via the app or a computer? I find the app being a bit easier to use, since you don't need the members account number.
If you are using the app:
1. Click on "Transfer/Deposit" then "Send Money"
2. Select the account you wish to transfer funds from
3. You will need to make sure you have the USAA members full name and phone number that is associated with their USAA account. Enter this information
4. Enter the amount you wish to transfer
5. Hit "Transfer"
6. Your recipient gets the money instantly
7. You will both receive a confirmation via text or email
If you are using via a computer:
1. Add the "other persons" account to the "account list"
2. You will need to wait for "validation" to be successful
3. You can then use Transfer between Accounts found in the Account Tools Tab to transfer funds
Hope this helps!