How do I display a category and its link after a post

The function is called the_category().
https://developer.www.ads-software.com/reference/functions/the_category/
If you need it, here is the Theme Developer Handbook: https://developer.www.ads-software.com/themes/

Thanks a lot Joy. I really appreciate. Please one last thing, where am I supposed to placed the code so it appear in my posts? Thanks

It would be in the appropriate template file or template part, depending on how your theme is structured. See Template Hierarchy. But you should not make changes to your theme, since the changes would be lost if the theme author releases a new release. Changes should be made in a child theme.
Or switch themes to one that already has the categories shown.

Thanks, Joy. I just found a way out.