Blockchain - Technical Side & Use

Question

Hello, I was recently researching about the Blockchain technology.
At first I saw it like a LinkedList, something we know from Computer Science, but is it really a LinkedList in its implementation?

I understood that it's used in Bitcoin etc, but how? I know that you can add a block to the chain and the block will appear on everyones computers without the ability to alter the data you put on the block. Now, how is it connected to Bitcoin and can you use these features of Blockchain?

And does Blockchain have their own servers? because from what I understand you can create you own block and connect it to the chain that is being replicated to everyones computers. So i'm assuming you send the block to their servers and then it updates every "fork" people did of the chain. Right?

Thanks.