Can I buy USDT by USD?

Excuse me, I'm a bit new to the cryptocurrency market. I was wondering if it's possible to purchase USDT using USD? I've heard about USDT being a stablecoin pegged to the US dollar, but I'm not sure how the buying process works. Could you please explain if it's possible and, if so, how I could go about doing it? Also, are there any specific platforms or exchanges that you would recommend for this purpose? I'd appreciate any guidance you could provide.