What are the different types of sharing in salesforce ?

Hi Aman,

Force.com Managed Sharing :-
Force.com managed sharing involves sharing access granted by Force.com based on record ownership, the role hierarchy, and sharing rules:-
Record Ownership:-
Each record is owned by a user or optionally a queue for custom objects, cases and leads. The record owner is automatically granted Full Access, allowing them to view, edit, transfer, share, and delete the record.
Role Hierarchy:-
The role hierarchy enables users above another user in the hierarchy to have the same level of access to records owned by or shared with users below. Consequently, users above a record owner in the role hierarchy are also implicitly granted Full Access to the record, though this behavior can be disabled for specific custom objects. The role hierarchy is not maintained with sharing records. Instead, role hierarchy access is derived at runtime. For more information, see “Controlling Access Using Hierarchies” in the Salesforce online help.

For more information you can refer to this link.