The image below is a simplified and easy-to-understand illustration of how hashing and salting work. The main takeaway from this post- multiple users can have the same password, but will all have different salt values, thus making their hash result value different, and when you authenticate, you authenticate by the hash result value of your passwords, which is virtually always going to be unique for each user record:
Even in the case of 2 users having the same hash result, the usernames will/should not be the same, so you still have distinct accounts, because UserID is also checked in the authentication process.
Simple, no?
Companies increasingly (and for good data privacy reasons) do not even store the clear text textbox value you enter when you sign up for and then log into Fb, Google, Amazon, etc- they check your entered password's hash result against the hash result they have for your user/account record either from when you registered or last changed your password.
Good answer to the question you may come across, "what is the difference between salt and an IV (initialization vector)?" (TL;DR: not all IV's are salt, but salt is a kind of IV): https://security.stackexchange.com/questions/6058/is-real-salt-the-same-as-initialization-vectors
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