There are some usefull links given below.
1. https://www.icai.org/
2. https://www.mca.gov.in/
3. https://www.aces.gov.in/
4. http://www.cbic.gov.in/
5. https://www.rbi.org.in/
6. https://www.tin-nsdl.com/
7. https://www.sebi.gov.in/
8. https://www.incometaxindiaefilling.gov.in/
9. http://www.ipindia.nic.in/
10. https://www.esic.nic.in/
11. https://epfindia.gov.in/
12. https://contents.tdscpc.gov.in/