If pogba signs for Monaco he will be a good player for them but he didnt play for a long time and i dont think he will be used to their gamestyle anytime soon. He needs to train with them a lot and get some playing time to help them because he didnt have any minutes in football for a long time. But if he plays like he knows he will bring them good quality
It is too early to judge that he will be good for Monaco. But since he is an experienced player and performed impressively in the past, we can assume he has a chance to contribute well for Monaco. It surely takes time to return to his best form anymore. However, the chance will be higher if he can be one of the main player in Monaco midfield line. Now, the most important thing that Monaco really signs him, so he really can be a part of Monaco squad for the next season. So far, Monaco is negotiating with Pogba, we still don't know the result.
Related news: https://www.espn.co.uk/football/story/_/id/45507105/paul-pogba-talks-monaco-ahead-return-action-sources