Where can I buy and exchange crypto?

Good day, I was wondering if you could help me understand where I can buy and exchange cryptocurrencies? I've heard a lot about the potential of digital currencies but I'm not sure where to start. Could you point me in the right direction? Are there any specific platforms or exchanges that you would recommend for a beginner like myself? I'm also curious about the safety and security measures I should consider when making transactions. Thank you for your time.