Where can I buy solidly?

Hello there, I'm curious about the best places to invest in cryptocurrency securely. Could you please enlighten me on where I can find reliable platforms or exchanges to "buy solidly"? I'm looking for platforms that prioritize security, have a good reputation, and offer a diverse range of coins to choose from. Additionally, are there any specific features or practices I should look out for when evaluating these options? I'd appreciate your insights and guidance on this matter.