How do I specify a category when transferring between bank accounts?

Transferring your funds from one bank to another is easy to do in QuickBooks Online, @stewartsbaker. Let me assist you on that. 

Re-categorizing your bank's funds is currently not available. In QuickBooks Online when transferring bank funds it will only give you choices of which bank it will come from and to which bank it will transfer. However, transferring your funds is possible.

 Let me show you how:

1. Go to +New.
2. Under Other, select Transfer.
3. Choose from what bank it will be deducted and transferred to. 
4. Provide the necessary information, edit the date, and enter a description in the memo field (optional)
5. Click Save and Close.

You can also check this article to learn more about transferring bank funds: Transfer funds between accounts.

Moreover, let me share these articles that can help you manage your banking in the future: 

• Deposit payments into the Undeposited Funds account in QuickBooks Online
• Transfer funds between companies in QuickBooks Online
• Unmatch downloaded bank transactions or move them to another account

Keep me posted if you still have concerns with your bank funds. Have a great day, and take care!