Whenever money goes into or out of the till without being a sale, record it as an Injection or a Withdraw. That's what makes the closing match the cash in the drawer.
The amount shows in green for an injection and red for a withdraw, so you don't pick the wrong one.
The amounts go into the cash register summary, totalled as Injections and Withdraws, and count towards the expected balance at closing. Each movement is listed with its date, amount and note — including in the closing PDF.
Injections and withdraws only affect the till. They don't create an entry in Financial.
If the money that left was a real expense (paying the delivery rider, say), record the expense in Financial as well. The withdraw explains the cash missing from the drawer; the expense explains the cost in your results.
It's what saves you a week later, when you look at the closing and can't remember why $50 left the till.