Want to edit "Reading Settings"

For each article in a feed, show

That’s for your RSS feeds – not your web pages.

Try using the <--more--> tag in your posts. See Customizing_the_Read_More.

How can I use RSS feeds for my blogs?

WordPress creates the feeds automatically: https://www.expertmagentodevelopers.com/blog/feed/

if I want my readers to subscribe my blogs via RSS feeds, what should be done. I tried to install plugin, but that didn’t worked ??

You don’t have to do anything – although you could provide a link to the feed in your theme’s template files.