Hello Seshapriya,
There are multiple websites online that provide free certification courses. The courses can be varied and it would be good to have an idea of the kind of courses you'd like to learn from online websites.
SWAYAM is a government run website that offers a wide variety of courses, ranging into multiple disciplines, all of which form a huge potential in today's real world market. You can check out the courses available on the official website.
The website link is: https://swayam.gov.in/
The process to find a course and learn it is very simple.
1. Visit the SWAYAM website.
2. Log in with your credentials or create an account, it is very simple.
3. Browse the catalogue and find courses that interest you.
4. Enroll for the course and complete the course according to the timeline set.
Good luck.