Is there an app to buy NFT?

Could you please elaborate on the availability of an application that allows users to purchase Non-Fungible Tokens (NFTs)? I'm curious to know if there's a specific app that offers a secure and user-friendly platform for acquiring these unique digital assets. With the rising popularity of NFTs, I imagine there would be a demand for a convenient way to buy and sell them. Could you provide any insights into which apps, if any, are trusted sources for NFT transactions? Additionally, what features should one look for in an NFT buying app to ensure a smooth and secure transaction experience?