How does a computer file exist is in the physical world?

I'm interested in a detailed explanation of how the physical aspects of my hardware give rise to a computer file that I actually interact with via the UI. More specifically, how is a single computer file stored in the physical world?

Is it a cluster of space on a hard disk riddled with various indents? Are those indents scattered across the disk? Is there some kind of electrical or magnetic component involved?

I have a vague idea that computer data is made up of 1's and 0's stored on a spinning disk that is read by a needle, but that still doesn't feel tangible enough.