How do people create shared accounts on Scratch without letting everyone know the password?

You can't. Shared accounts aren't allowed (unless you live in the same house as the person you're making an account with) and there isn't any way to make one without everybody knowing the password.

shared accounts aren't allowed.

As the others have said, these aren't allowed. I'd recommend against trying to make one.

Also, with the way Scratch works right now, for multiple people to sign on, you need everyone to know the password anyways. The easiest way around that would be to type the password for them on their device in person.

Shared accounts aren't allowed except with close family members. Eg: Brother

Chimp-Master wrote:

How do people create shared accounts on Scratch without letting everyone know the password?

You shouldn’t do it with people you met online, only with people you know in real life. Make sure you trust the person, too. I’m pretty sure you can only do it with people you live with, but I think it might be fine for, let’s say, your best friend that you have known for 5 years.

Since I don't think the people above actually answered OP's question: Probably through a comment that the creator deletes or through other chat platforms.

They aren't permitted on scratch unless it is an account with a sibling, or family member in the same household (I believe)