How can we create custom Permalinks in WordPress

How can we create custom links in a WordPress site.
Like
https://www.mysite.com/products/rocket
https://www.mysite.com/products/bike

OR
https://www.mysite.com/generalchemistry/mole
https://www.mysite.com/generalchemistry/mole-lecture2

and if we open just
https://www.mysite.com/products/
OR
https://www.mysite.com/generalchemistry/
than all related posts or pages related to products or generalchemistry show.

Kindly help me in this regard.

Thanks