Go to AP-Tools-Check Format. You can select the check format that you use (this is located in Cash Management, on the bank account setup) and change the check stub location to "Below check face" instead of "Above check face". I've attached a screenshot of the Check Format Setup so you can see it. 

Hi Karp -

While the procedure that @Kaysong70 has detailed out will get the output check file to generate the check stubs at the bottom and the check on top, that isn't the way that PrintBoss works.  PrintBoss comes with a Sage300CRE check format called TL_AP5.  It is expecting the check to be exported from Sage300CRE with 1 check stub at the top and then the check face in the middle.  Then PrintBoss reads this "Raw Capture" of the output file and changes it into a check fully formatted with 2 check stubs at the top and the check on the bottom.

If you ordered blank check stock to be check on the top and 2 stubs at the bottom, then I think you will need to work with PrintBoss or a consultant that knows PrintBoss to move the check elements around within PrintBoss to print to your blank check stock.  I have worked with PrintBoss for quite awhile and I have never seen a form file in PrintBoss that is compatible with Check on top stock.

Cheers,

John McLagan
Independent Senior Consultant
Johnny on the Spot