Hey there, @Kim301.
Thanks for taking the time to reach out to the QuickBooks Community. How are you doing today? I hope all is well.
For the account number to appear in the Memo field of the bill payment check, it must be entered in Vendor Information before using Bill Pay. Since you stated that you have already entered the account numbers, are you currently using Bill Pay to pay the vendor directly or are you just marking the bills as paid?
Please know the account number will only be automatically entered in the memo field when using Bill Pay. For more information about this process, check out Enter the account number in vendor information in QuickBooks Online.
I understand how having the option to populate the account number without using Bill Pay could be handy. That said, I think this is the perfect opportunity to share this idea with our Product Development Team. Our Developers review each request and consider them all for future updates. You can use the link I'm including below to share your thoughts.
Please don't hesitate to let me know if you have any additional questions or concerns. Have a good one!
