I'm here to help transfer ACH connections from your QuickBooks Desktop (QBDT) to QuickBooks Online (QBO).
Just to clarify, are you referring to transferring your QuickBooks Payments account from QBDT to QBO? If so, you'll need to disconnect it from your QBDT and connect your QuickBooks Payments account to QBO. Here's how to disconnect your QuickBooks Payments account from QBDT:
Open your QuickBooks Desktop company file.
Go to the Home menu, then click F2 on your keyboard.
Click Yes on the prompt to unlink the AuthID.
Once done, you can now connect it to your QBO account. Let me guide you how.
Sign in to your QBO account as an admin.
Click the Gear icon, then select Account and Settings.
Go to the Products and services menu.
In the Existing account section, select Connect or Link Merchant Service.
Click the QuickBooks Payment account you want to connect. Then, select Connect.
Review the account info and make sure it's accurate. If everything looks good, choose Connect.
When the connection is finished, sign out and sign back into QuickBooks Online.