Object-Level Security (Permission Sets and Profiles)
Using object permissions you can prevent a user from seeing, creating, editing, or deleting any instance of a particular type of object, such as a account or decision.
Field-Level Security, FLS (Permission Sets and Profiles)
FLS helps you control whether a user can see, edit, and delete the value for a particular field on an object.
Record-Level Security (Sharing)
Record-level security lets you give users access to some object records, but not others. Every record is owned by a user or a queue. The owner has full access to the record.