What for with to register a tag more in the text?

Question

Search Engine Optimization

And where exactly should it be written?

Answer 1

This tag allows you to better design the individual post page and the list of posts. So that the site understands what part of the text to display in lists (for example, headings). Usually there is some kind of introductory part of the post and after it the tag more is placed. Then, if you open a section where there will be 10 posts, then in addition to the title and picture, there will be a short introduction about what this post is about.
It all works if the theme supports such a mechanism. There are topics where this does not work and there the presence of this tag means nothing.