Easiest way to understand it is that its like a VPN but... better. You can do VPN-y things like access different locations and itll give you an IP address that isnt your own but its a lot stronger when it comes to keeping you hidden online. You can use it for web scraping or automation or other general marketing or research things. Theres three types; residential, datacenter, and mobile. Each one has its ups and downs. Personally, I like mobile proxies because they tend to be more secure, especially when it comes to doing social media automation. But it is sometimes expensive. Datacenters are cheap but most of the times the IP is already detected so it wont do much good. Residentials are just the standard, middle ground of everything. Basically the only difference between the three is where they get the IP address from. Residential get it from ISP addresses that are given to people for this houses, datacenters come from a literal datacenter that hosts servers (sort of the closest to how VPNs operate) and mobile proxies get IP addresses assigned to mobiles which are harder to ban since at all times more than one person is using it and theyre ever changing. Its really interesting to be honest. Worth looking into for curiosities sake