Where can I find ERC20?

I'm quite interested in ERC20 tokens and I'm looking to get started with investing in them. But I'm still at a loss as to where I can find them. Could you possibly direct me to some reliable sources or platforms where I can buy and trade ERC20 tokens? Also, could you provide any tips on how to safely and securely handle these transactions? I'm still quite new to this crypto world and would appreciate any guidance you can offer. Thank you in advance for your help.