Why some codes ends different. For example <body/> and <p/>. What difference between them?

Answer 1

in html there are tow types of tags,
opening tag and closing tag,
some tags in html don't have closing tag
like <img/> <br/> <meta/>.
and like <p>.........</p> this is normal tags
have opening <p> and closing </p>

Answer 2

which come after / have apenning tag and this be in closeing one .
which come before dont have openning and closeing . its on code like <br/>

Answer 3

I mean why some words are coming after this symbol "/" and why some of them coming before that symbol.