My posts doesn't display the content on Google.

What should I do that my content of the post to be displayed on Google directly under the title of the post? I understood that I should block something in robots.txt?

That’s because when I am making a post and it is indexed on Google, under it appears the title of the site, or the description of the site, or a text widget, I don’t know.

I want my content of the post to be displayed under the post directly.

Please help. Thank you in advance.