At the moment, creating a transfer in QuickBooks Online through the mobile app isn’t possible. You may consider logging in to the program through a web browser to record the said entry. Then, follow the steps below.
Press the + New button.
Select Transfer.
From the Transfer Funds From the dropdown list, select the bank account that the money is coming from.
In the Transfer Funds To dropdown, select the bank account where the funds are going.
Enter the date and the amount.
You can also enter a description in the Memo field.
Click Save and close.
You check this article to learn more about recording a transfer between two accounts in QuickBooks Online: Transfer funds between accounts.