How to remove something from the slug/url
In Craft 3 under your section config change the URL config

https://docs.craftcms.com/v3/sections-and-entries.html#sections

SEE: Entry URI Formats

You can select what template it should render and what URL config you want

Failing this you can use something more advanced:

https://docs.craftcms.com/v3/routing.html#advanced-routing-with-url-rules