Thank you suggesting to make the check template customizable, CJDay. I'll share this with our engineers.

I've heard other users are able to print checks from other vendors in QuickBooks with no issues. However, we can't guarantee if checks from other vendors will always work in our program. 

On the other hand, we offer compatible checks that you can use in your daily transactions. You can order through QuickBooks Checks & Supplies. Just hover your mouse's pointer on the Phone icon to get the number.

You can always go back to this thread if you have other questions on checks.