Notes
To view the sharing settings page, from Setup, in the Quick Find box, enter Sharing Settings, then select Sharing Settings.
There are several sharing mechanisms that you can use to configure record access for your users.
Organization-Wide Defaults
Your organization-wide default sharing settings give you a baseline level of access for each object and enable you to extend that level of access using hierarchies or sharing rules. For example, you can set the organization-wide default for leads to Private if you only want users to view and edit the leads they own. Then, you can create lead sharing rules to extend access of leads to particular users or groups.
Role Hierarchy
The role hierarchy automatically grants record access to users above the record owner in the hierarchy. You can control sharing access using hierarchies for any custom object, but not standard objects.
Sharing Rules
Sharing rules represent the exceptions to your organization-wide default settings. They allow you to extend record access to users regardless of their place in the role hierarchy. If you have organization-wide sharing defaults of Public Read Only or Private, you can define rules that give additional users access to records they don’t own. You can create sharing rules based on record owner or field values in the record.
Manual Sharing
Sometimes it’s impossible to define a consistent group of users who need access to a particular set of records. Record owners can use manual sharing to give read and edit permissions to users who don’t have access any other way. Manual sharing isn’t automated like organization-wide sharing settings, role hierarchies, or sharing rules. But it gives record owners the flexibility to share particular records with users that must see them.