Why can’t I install Flash Player in Tor browser?

Hi,

My client's website Apps Innovations is not working well on Tor Browser. It is working well on Google Crome, Mozilla Firefox. Everything is good from my side but my client is checking on tor browser thats why some error are showing. I suggest to my client to install Adobe Flash Player but he is not able to install flash player on Tor Browser. Please help and suggest how to install Adobe on Tor Browser as I also come to know this browser name first time and have no knowledge about this.

Thanks