Hello carol42, 

You can certainly choose to do this if you do not wish to connect your account directly. 

To do this, go to Accounting > Chart of Accounts > New, and select the Account type as 'Cash at Bank and in hand' and the relevant detail type. You can then rename the account here under '* Name' and enter an opening balance (the balance of your bank account when you began recording transactions in QuickBooks Online).

You can then either enter the transactions manually or import the transactions from a CSV file, which will allow you to use the Banking page in the same way as if there was a live connection by adding and matching transactions. 

You can see how to import the the transactions using a CSV file on the link below: 

https://quickbooks.intuit.com/learn-support/en-uk/help-article/import-transactions/add-older-transac...

Thanks