What mean blog project <h1> and it is different from paragraph.

Answer 1

<h1> text size
<h1> - <h6>
from the largest to the smallest

Answer 2

You mean, you wanna know the difference between <h1> and <p> tags? p sets the block of text on the page: so on your page appears some area for text. h1 exists for mostly 2 things: to show, that it's the most important header on the page (or one of the most) to 1) the viewer (simply, it's the biggest header on the page), 2) to the websearch resource.