Is world2sms is a fake or real company?
They are providing an offer to earn by sending SMS of company ads through free websites. And they are demanding Rs. 500 for an enrolment to membership

They are providing me an offer to earn by sending SMS of company Ads. Through free websites. And also providing offer to work as a full time/part time from home or from anywhere. For this they are demanding Rs. 500 for registration/enrolment.

So they are trying to charge you to spam cell phones.
Well it seems like THEY have the right idea in this business model..

Buyer beware. Before paying anyone money for a service, check them out on the internet, and through local or regional regulatory agencies.

If it were me, I would not pay a company that I've never heard of to do do what you describe.