What to do after 18?

Ok y'all im not gonna write a para or so. I just wanted to ask the legal stuff in supposed to do after 18. I'm already 18 and over and I did nothing except opening a bank account. So can someone tell me the stuff I need to do? Like apply a pan card and other stuff? If possible guide me on how to and only the important steps pls 🥹 I feel like I did nothing after I turned 18. I changed my aadhar pic and that's all I did. Tldr: Basic legal and necessary stuff to do and apply after turning 18.