I want to automatically create user and assign task to user group

Can anyone please guide me in this.
Thank You

Can you elaborate more on automatically creating usecase? And why you want do that?

You can leverage Identityservice for creating users

I will be getting users list in google sheet format such as first name, lastname, email. So from this list I want to create user account in camunda for all those users and I want to assign them task such as forms and after that I want to process the information which I will be getting from forms.

You can create a User via API and there are also some actions in the group part of the api reference.
See more on these two links:

For Creating the Client you can probably use the OpenApi Spec from Camunda, please check first if this part of the API is covered

If I remember correctly, you can also integrate different authentication options like keycloak or ldap which would expand your options of managing your users.