what types of audit features salesforce provides us?

To verify that your system is actually secure, you should perform audits to monitor for unexpected changes.

Record Modification Fields -

All objects include fields to store the name of the user who created the record and who last modified the record. This provides some basic auditing information

Login History -

You can review a list of successful and failed login attempts to your organization for the past six months

Field History Tracking -

You can also enable auditing for individual fields, which will automatically track any changes in the values of selected fields. Although auditing is available for all custom objects, only some standard objects allow field-level auditing.

Setup Audit Trail -

Administrators can also view a Setup Audit Trail, which logs when modifications are made to your organization’s configuration.