Access rights are how you define which users are allowed to do what with the files and folders that you share with them.
You can grant users the following rights when you share files and folders with them:
Viewer: Users can view individual files that are shared with them, or all files within the folder that is shared with them.
Editor: Users can view and modify individual files that are shared with them, or all files within the folder that is shared with them.
Contributor: (Applies only when sharing folders) Users can create files in the folder, rename existing files, modify files, move files, and delete files inside the folder. Users cannot perform actions on the folder itself.
The recipient can share this item with others: Select this check box if you want to allow the recipient of the share to share the item with other users, then select whether you want them to be able to share with internal users, external users, and the public.