When you connect your bank account, QuickBooks Self-Employed (QBSE) automatically downloads the 30 to 90 days of the transactions. If the transaction you want to import is older than the ones in your account. You can import them manually. Let me guide you how.
Sign in to your bank's website.
Follow the instruction on how to download the transactions as a CSV file.
Set the date range and follow the on-screen instructions to finish the download.
Once done, open your QBSE.
Go to the Gear⚙ icon and click Imports.
Select the account you want to add the transactions into.
Click Browse and find the file you downloaded from your bank.
Select the file and click Open to start the import.
Review the column headers and data, then click Continue to complete the import.