مشکل در ساخت فایل py به فایل exe

این ارور را می دهد
pyinstaller : The term 'pyinstaller' is not recognized as the name of a cmdlet, function, script file, or operable program. Check the spelling of the name,
or if a path was included, verify that the path is correct and try again.
At line:1 char:1

• pyinstaller --onefile -w .\main.py

• 
  + CategoryInfo          : ObjectNotFound: (pyinstaller:String) [], CommandNotFoundException
  + FullyQualifiedErrorId : CommandNotFoundException
  لطفا هر  کسی جواب را بلده کمک کنه ممنون.