Open your padlet and select ‘Share’

Select ‘Change Privacy’,

Select ‘Secret’ which allows people who have the link to join the Padlet.You can limit what they can do by selecting the visitor permissions –‘can read‘, ‘can write’ or ‘can edit’

This one : https://universityofbrighton.padlet.org/rse11/nho7n7ybdo8xrddt  is set to allow anyone to edit… which is a bold choice 🙂