Final answer:
Users see the sharing button on an object when they have edit access, which lets them modify the object's permissions.
Step-by-step explanation:
Users would see the sharing button on an object when they have specific sharing permissions. Ideally, users see the sharing button when they have edit access to the object. Being the record owner or having delete access does not specifically control the visibility of the sharing button; it is more about the edit permissions set within the system for that object.