I'll share information about creating a check in QuickBooks Online, @Philip5410.
Currently, there is no option to populate the customer's name when creating a check. You can pre-fill the Category details when you enable it in the Accounts and Settings. See the screenshot below:

For future reference, you can check this article as your guide to print checks in QuickBooks online: Print a check in QuickBooks Online.
Feel free to comment below if you need more help creating checks in QuickBooks Online. I'm always here to help. Have a great day.