Is it possible to give money in cash at the counter and make a transfer without it being visible in my own account (Postbank)?

Hello, The title of my question says it all. I would like to transfer money, but it is not recorded under transactions on my Postbank customer account/online account. Can I give the money in cash to the employee at the Postbank/Deutsche Post counter and transfer the money to the recipient via bank transfer slip? (I…