How to provide security for the Records (Instance) in Salesforce?

Record level Security in Salesforce can be achieved by following:

1. Organization Wide Default(OWD): Default level of access users have to each other’s records
2. Role hierarchy: Each role in the hierarchy represents a level of data access that a user or group of users needs.
3. Sharing rules:utomatic exceptions to org-wide defaults for particular groups of users, to give them access to records they don’t own or can’t normally see.
4. Manual Sharing: lets record owners give read and edit permissions to users who might not have access to the record any other way.