Use whatever local platform you have in your country that has a good public reputation. Generally though, I personally use Binance P2P.


Also, if you're not knowledgeable about Bitcoin/crypto yet:

* If you like reading articles: https://coindesk.com/learn
* If you like reading books: https://theinternetofmoney.info/
* If you like watching videos: https://www.youtube.com/playlist?list=PLPQwGV1aLnTuN6kdNWlElfr2tzigB9Nnj

Security related:
* https://chainsec.io
* https://www.lopp.net/bitcoin-information/security.html

If you want to get more technical
* https://github.com/bitcoinbook/bitcoinbook#chapters