Is it necessary to add the tag <p> or can we use any other tag

Question

Can we use tags like <c>, <h>, etc.

Answer 1

No you cannot make tags of your own. You have to use tags that are available in html. Instead of <p></p> tag you can use <div></ div> tag.
Tags that you have mentioned are not valid.

Answer 2

://You can use them but they are not valid html tag, As <p> tag is block level element instead if you use <c> or <h> they will be inline elements

Answer 3

HTML5 has predefined elements that fullfil one goal. For example <p> is for paragraph, <a> for links or <h1> for level 1 headings.