What is the difference between a Record's Status and a Record's Phase?
Phase
A Record's Phase is configured in the Process Builder (i.e., App Wizard). In the screenshot below the Phases are: 'Frozen/Blocked', 'Being Researched', 'In Progress', 'Ready for Review', and 'Complete'.
Tip: On Apps that do not have any Phases configured, the default is phase is "Phase 1".
Status
A Record's Status is either 'Pending' or 'Complete', there is no other status. The only way to move a Record between 'Pending' and 'Complete' is to use a Close or Reopen Action.
Gotcha: When a Record is in 'Complete' status it cannot be edited from the UI, and certain Actions such as Generate Document or Generate Spreadsheet targeting the Record's attachment Field will fail.