How to account for someone giving me cash?

My daughter got some cash from friends for her birthday. She gave me $20 cash to put into her betterment investing (we set up an account for each kids last year for them to see their money "grow").

I put the $20 in my pocket and then transferred $20 from my checking account (which is linked in ynab) to her investing account (which is outside of ynab).

If I don't want to go to the back to deposit it, how do I account for this?