Allowing other users to view or edit information you own. There are different ways to share data:

• Sharing Model—defines the default organization-wide access levels that users have to each other’s information and
• Role Hierarchy—defines different levels of users such that users at higher levels can view and edit information owned by or shared with users beneath them in the role hierarchy, regardless of the organization-wide sharing model settings.
• Sharing Rules—allow an administrator to specify that all information created by users within a given group or role is automatically shared to the members of another group or role.
• Manual Sharing—allows individual users to share a specific account or opportunity with other users or groups.
• Apex-Managed Sharing—enables developers to programmatically manipulate sharing to support their application’s behavior. See Apex-Managed Sharing.