Dear Laxmipmc,
Your business comes under “Third Party” Business. Earlier companies used to give sub-contract for a fixed price in r/o unskilled, and other staff. But now there are many agencies who worked on Service Charges @ % basis on monthly outsource costing. Still the job is also comes under Contract Labour (R&A) Act, 1970. Even if your liability is fixed upto salary, PF and ESI still it is a “Sub-Contract”.
Labour licence is applicable where you deploy 20 or more labour in a single place agst a single Agreement. Even if agst a single agreement you deploy 20 or more in the same jurisdiction, the Labour Office can ask you to obtain Labour Licence.
Here one important point is that if the company (for whom you are working) is a contractor company (Being prime contractor of the location) and they have Labour Licence in r/o all deployed labour/staff. In that case you can ask them to issue you a certificate duly mentioning “the deployed menpower at site is included in their Labour Licence”. Than you will not require to take any Labour Licence for that site.
For the other Registration, the fellow members have already clarified.