Hi @rsneharani,
Are you trying to change your display name here in the Community or in your Canvas itself? Here in the community, I think someone like @KristinL would need to change your username for you. In Canvas itself, you may have the option to change your display name from within Canvas, but many schools/institutions tie the names in Canvas to other systems and would direct you to change them somewhere else which would then update Canvas through automation. In that scenario, it would be best to reach out to your local Canvas administrator (usually in the eLearning / IT / Digital Education areas) to find out what the process is, as we don't know that kind of information for each individual school/instituion here in the global community.
Hope this helps!
-Chris