When we start arranging blogs in categories we put some name.
But how can we show that categories name to the post specific to it?
On a post, to display the category that post belongs to you would use {{ page.category }}
And how to link it to its category page.
The same way you call it in above. Add that variable to a href.
Just note that Jekyll doesn’t create category pages for you, so just because you use something like <a href="/{{ page.category }}">{{ page.category }}</a> in your layouts doesn’t mean it will resolve.
You’ll need to manually create those archive pages or use a plugin like Jekyll Archives to do it for you.