Where to edit ingress text beneath post header on index

It looks like the content of the respective post.

Can you share the URL which has this problem?

URL to index is:

https://educate.no/freerunning

To article:
https://educate.no/freerunning/10-good-reasons-why-running/

The screen dump is taken from https://educate.no/freerunning

The text below the post title is the excerpt. It is created by WP from the first 55 (I think) words of the post content. So, if you change the first part of the post content, it will be reflected in the excerpt. The other way to change it is to create a manual excerpt. In the post editor, below the post content, should be an Excerpt option. If you don’t see it, click the Screen Options tab in the upper right of the editor screen and select “Excerpt”. Then you can enter your own excerpt which will override the default.

I can not see the excerpt option below the post content. When selected excerpt from screen options, it still does not appear.

It’s only available on posts, not pages; if you’re editing a post then you should see it. Do you have any plugins that affect posts, like Advanced Custom Fields?

It’s not availeble in my posts. I do not have the plugin you mention.

Ok, now I have excerpt option in my posts. Thank’s for all help!

You’re welcome; glad it’s working.