Why is the post not showing in full?

Question

WordPress

installed pure wordpress;
added post - copied text with P and H2 tags;
everything is correct in the editor, but on the page in the public part the text of the post is not displayed in full;
text about 10 paragraphs

Answer 1

Due to html structure - there were nested P tags like

<p>
    <p></p>
    <p></p>
</p>

Answer 2

Most likely this is a preview of the text
<?php the_excerpt(); ?>
Try to fill in the excerpt below, will the text change