mPDF Checkbox field need to print a "OK" instead yes or no

Im using mPDF in a CRM that passes the variable to print in checkbox fields 0 for not selected and 1 when selected, reading it from the database.

When trying to print this variable prints YES or NO. My question is... how can I print a "V" (bissé) instead yes, and " " (blank) insted of no?

Thank you so much for your help