1.Search about the the topic or domain on which you want to contribute like changes in style, resizing, changing fonts, etc.
2.Take the reference from below example and structure your information similar to that .
3.Check whether the contribution you are providing is valid.
4.Commit your change and go for pull request.
NOTE1 - Contribution must be done in the given format. Pull request wont be accepted if the format is wrong.
NOTE2 - Contribution you are providing must be applicable in web and valid.
5.Example :
- Adding paragraph tags in given spaces of html file .
- Then styling it in the css file .
PREVIEW :
HTML- <p class="contributorName"> Hacktoberfest is a oper source contributing and moderating event </p>
CSS- .contributorName{
color: white;
}