We use GoHenry and they have their own debit cards. Money auto transfers.

DD is 10. I set up an account at my bank (it's "my" account, just designated for her) and I auto-deposit $20/month. That's also where any significant amount of her earned money goes, like from pet sitting. She basically never sees or spends it.
The less significant amounts of cash, like change and small bills, sit in a piggy bank and are available for candygrams at school or whatever other minor expenses.

Weekly allowance in cash not tied to the routine chores they are expected to do around the house. Those are their contributions to keeping the household running.

Extra chores (like big organization projects) are up for grabs and tied to dollar amounts that they can earn upon completion.

DS gets five dollars a week to spend as he chooses. Chores aren't tied to the allowance and are just expected to be completed.

We keep track of the his money on the family calendar and just add funds at the start of the week. We started doing this way so he could learn how to do the math and never changed the process.

I have it on automatic transfer of $100 a month on the second of every month to her debit card. She has two chores that she has to do or arrange for them to be done by someone else - I don’t remind or do the substitution arrangements. I have a list of what she has to spend her money on. For example I hate nails and will never spend my money on anything nails. If she doesn’t have her debit card and I pay for something I do an immediate transfer in her presence to my account.

I was terrible at this for my older kids. One had mental health issues and between hospitalizations I didn’t want him to have money I didn’t control. The oldest got a job by the time I would have given him allowance. He was a kid that didn’t need much money before then - didn’t go out with friends or want much.