Let's try changing the page scale to achieve a better fit, HugoSyd.

After selecting Print, choose Shrink to Printable Area from the Page Scaling drop-down. If the same issue persists, try adjusting the alignment while using our QuickBooks-compatible checks. 

Please check out this article for tips on how to adjust the alignment: how to adjust the alignment: Learn how to fix the alignment when printing paychecks using QuickBooks-compatible checks. It'll show you how to set up printing preferences and check the alignment.

I'm also adding this article for other troubleshooting steps you can try: Fix QuickBooks Online printing issues on browsers for Windows.

I hope you find the information I've shared easy to follow. Let me know how this goes by commenting below. I'll stay around and check the results. Or provide additional steps when needed to fix the alignment.