You can still add and capture receipts in QuickBooks Online even if your bank account is not linked or connected on file. In QuickBooks Online, you can add receipts in three different ways:
Scan the receipts directly through the QuickBooks mobile app.
Drag and drop the image, or upload it into QuickBooks Online.
Forward the receipt by email.
To upload receipts in QuickBooks Online:
Click on the Banking tab, and select Receipts.
Click on the For review tab.
Under Actions arrow review the receipt and categorise them.
Select Review if no match is found and follow the prompts.
If you're asked to allocate to a bank account but your online banking is not connected in QuickBooks Online, you can manually create a dummy bank account in your Chart of accounts.
Click on the Accounting tab.
Click on Chart of accounts.
Click on New button.
Under Account and detail type select Cash and cash equivalents.
Enter a Name for the bank and how you want to show on your report.