Most blogs (like this one) show only a part of their posts on the home page. For something that is so common one would expect that WordPress comes with a built in option to make this happen. But by default WordPress shows you complete posts, and surprising there is no option to change this in WordPress itself.
To show only an excerpt of your post you have to rely on your WordPress theme (and pray that it supports this feature).
This blog uses Sparkling Theme by Colorlib. Thankfully, it allows you to show an excerpt instead of the full post. To do this, head over to your admin panel. Under ‘Appearance’ select ‘Customize’. This allows you to customize the aesthetics of your webpage.
Once you’re hear, if the theme supports some extra features it will appear as [Theme Name] Options. Here as we use Colorlib’s Sparkling Theme we see ‘Sparkling Options’.
Once you select this menu, you should have a ‘Content Options’ menu. Select it.
This usually has checkbox that looks something like this:
Select it and click save. If the checkbox was already selected, deselect -> save, then select and save once more.
If you can’t find something similar in your theme, tough luck. Default themes like Twenty Sixteen don’t seem to support this option.