The Salesforce Organization (Org) ID is the unique identifier for your Salesforce Environment. Use the steps below to find your Org ID:
Click Setup.
For Lightning:

For Classic:

Navigate to Administration Setup > Company Setup> Company Information. (Type 'company' in the Quick find Box.)

There is a Salesforce.com Organization ID field starting with 00Dxxx. This is your Salesforce Org ID.
