I have a closed business checking account but hard copies of all the transactions made on it. Is there anyway I can upload those to fill the gaps in missing months?

Hi there, @leviathproductio.

Sure! You can enter those transactions in Excel and save them as .CSV file format. You'll want to check out this link to ensure your file is in the correct format before you upload it.

Then, follow the steps to manually upload your transactions in QuickBooks Online:

1. Go to Bookkeeping, then Transactions. 
2. Select Bank transactions, then click the blue tile for the account you want to add the transactions into.
3. Click the Link account dropdown, then upload from a file.
4. Click Select files and select the file you saved. Then click Continue.
5. In the QuickBooks account dropdown, select the account you want to upload the transactions into. Then click Continue.
6. Follow the onscreen steps to match the columns on the file with the correct fields in QuickBooks, then Continue.
7. Select the transactions you would like to import. Then select Continue and then Yes and Done.

In case you encounter some issues or see an error message, follow the steps to fix errors while uploading your transactions.

Let me know if there's anything else that you need help with. I'll be with you and guide you again.