HTML coding issues

How to use multiple style properties in a single HTML element ? For example if I want to us background color and text color properties in a single heading, then what will be the syntax ?

You can just continue on a new line within the brackets:

  background-color: black;
  color: white;

For example

<!DOCTYPE html>

<h1 style="color:green;">This is a heading</h1>


Now how to use another style in the same heading?

I cleaned up your code.
You need to use triple backticks to post code to the forum.
See this post for details.

Note that inline styles are considered a bad practice, but it works the same as with a separate stylesheet. You can just add new styles separated with a semicolon:

<h1 style="color:green; background-color:black">This is a heading</h1>

Thank you very much…