Hi. This question is about bitcoin block structure, not about mining.
This means that
* if you're a technical guy you should move the topic to Development & Technical Discussion; then you'll get good technically accurate answers. (this would be the best option imho, this looks like a technical question to me)
* if you're a not so technical newbie, this may better go to Beginners & Help.
Now, about your question, you may not have been looking for the right websites. And sources of information.
One direct explanation come from https://learnmeabitcoin.com/ which is one very good source for learning:
If you go to the source of this quote, you'll get more details.
Related links:
* https://learnmeabitcoin.com/technical/block-hash
* https://learnmeabitcoin.com/beginners/blocks
* https://en.bitcoin.it/wiki/Block
* https://en.bitcoin.it/wiki/Mining
* https://en.bitcoin.it/wiki/Block_hashing_algorithm