How to change date on deposit slip, which only prints current date?

It's nice to see you here, @lichten47J,

I can guide you through the steps on how to edit your deposit slip date. Follow the instructions below:

1. Navigate to Accounting then Chart of Accounts.
2. Look for the account register where the deposit is saved.
3. Tap the View register link under the Action column.
4. Click the deposit transaction then edit the date.
   
5. You can also use the Edit button to open the deposit transaction and edit the date from there. Then press Print after.
   
6. Once done, save the entry.

I'm attaching this link about printing deposit slips in QBO for your reference: Set up and print deposit slips

If you have other questions or concerns about deposits or anything about QuickBooks, let me know in the comment below. Have a nice day!