Module PDF

Hello i have the version opigno1.44 i have try to put the wkhtmltopdf module(with module install) but i don't have the thing for activate it in Administration » Configuration » Interface utilisateur » Printer, email and PDF versions » PDF i have inactive the dompdf module you can see one screen capture here!Ap75Qf2G-S04iHYxS5Qtti--I8VW?e=I80rZh how can i resolve the problem? thx for your help