>>105738925
It's just a hashing algorithm.
A hash is just a unique value created by a mathematical algorithm. It's used to verify that information hasn't been changed which is useful for security/privacy and troubleshooting/debugging.
If the data has been changed in any way, no matter how small, it will have a different hash.
So you can verify that you've downloaded the full file with no malicious or unintended modifications by taking the hash of what you've downloaded, and comparing it with the hash on the website.
You don't *need* to check the hash of anything you download, but it's not a bad habit to get into if you care about security. Generally files with large sizes are hosted on unofficial mirrors, and bad actors could try to upload their own compromised files into those mirrors, or make their own mirror to host those compromised files.
I would definitely do it for any important software like your operating system. Windows PowerShell should come with commands for checking the hash of a file, look up how to use them.