If you want to log out of your RoosterMoney account from the app, open the quick navigation window by tapping on your profile picture in the top left corner.
From there you will see an option to 'Switch user' or 'Log out'.
If you are wanting to login to another member of the family's account, tap on 'Switch user' which will take you to your family's login page. From there you can tap on a family member, enter the pin or password associated with their account to log in.
If you want to log out so your child can't access your account from your phone, using 'Switch user' effectively logs you out, but you won't have to re-enter your email address to log back in, unlike if you choose to fully log out.