What is "tags"

Example of an HTML code snippet

 <!DOCTYPE html>
 <html> 
   <head> 
     <title>Título da Página</title>
   </head>
   <body>
      <p>Conteúdo</p>
   </body>
 </html>

The tags above are some tags. The name "head", for example, indicates the beginning of the header and is closed by the tag , which contains the title "title", so when we open a tag, we close it with "/", however there are some exceptions, they are:

<br>; <hr> e <img>.