I will explain what ping is, just for the sake of it 
Basically, when you connect to a website, let’s say roblox.com, you send a request to Roblox’s servers. These servers are machines / computers, just like your PC at home. These servers (or computers) are just the same as your own computer, but they are usually better equipped with CPUs, RAM, GPUs and more.
Now, when you visit roblox.com, you are sending a request to these computers, and in most cases they will respond. Ping is the time it takes for you to send a request and get a response from these servers.
Now I’m going to see what the ping is when I visit Roblox!
It might seem confusing at first, but don’t worry! If you look all the way to the right, you can see the time it took for my computer to send a request to their servers, and for those servers to respond back. This time it took 131 ms before I got a response. This is the “ping”.
The reason why you can get huge pings are mainly because of slow servers, or if you’re far away from them. The internet is literally connected with wires that go under the ocean. When you visit any website, or play any game you send a request that goes through all of these wires to find the right “location”.
Below you can see how the internet is connected.
The lines you see on the image are actual wires that lie under the ocean, and are routing all requests. Since I live in Norway (which is far away from the US), it takes more time before the servers receive and respond to my requests.