index.php url after the domain name, wrong perma link structure

[Grandma]

Hey. I've got a problem with perma link structure and I tried everything but don't know how to fix it. 

after domain, there is /index.php/ on each page of the website. 

How to fix it? 

Thanks!

[Jim M]

Would check the response here:

https://invisioncommunity.com/forums/topic/456888-friendly-url-rewrite/?do=getNewComment