Create several users+password for an application (shiny standard plan)

Hi!

I'm making this application, which is private. I have to add users, but instead of sending invitations to each of them, I would prefer to create their accounts and passwords.
Is there a way to do that while private? or should I make it public and create my own login?

My users are not too techie to handle the standard shiny invitation and creation of password

Thank you