I want CRM users to view only their deals, leads, and contacts in the pipeline. What should I do?

Administrators can set access rules from Settings > Sharing Rules page in Vtiger.  Admins can control access at the module level and choose from one of the five different sharing modes:

1. Public (has three modes)
   1. Read-only: Users can view other's records (along with their records) but cannot modify or delete other's records
   2. Read-write: Users can view and modify other's records
   3. Read-write-delete: Users can view, modify or delete other's records
2. Private: Users can view only their records and records of other users with a role below this user's role in the hierarchy
3. Record-level: Only the owner and co-owner(s) of the record can access the record.

Note: Admin can always access all records

Please view Sharing Rules article for more details.