Thank you for posting in the Community. I'm here to provide some information about using these checks for printing in QuickBooks Online (QBO).
Here in Intuit, we have prepared checks that are specifically designed to be compatible with QBO, you can order these at our Intuit Market. While you can still use other checks, like the ones you have, we couldn't guarantee that they will print properly.
To confirm if they are compatible with QuickBooks, try printing sample checks and verify if the alignment printed correctly. For additional insight about this, I recommend following these articles: