In Chime, the credit builder is attached to the account you just go in and request a credit building card and you one. Each time you move money to it, it allows you to spend it and it will help boost your credit no matter what purchase it is.
With current, you have to put $100 first and then you can go in with micro transactions but in the long run this will also help you with building it also. These both go great hand in hand because you can double boost your credit without even having to have a credit card.
I highly recommend this. Oh, don't worry you can also put your direct deposit on them and it will help even more. You also get perks and can get cash back on certain purchases from stores which is a win win and I highly recommend it.