Sales Process is mandatory for creating Record Type in Opportuity.

Sales Process is used to create and maintain the Sales Processes used within our
organization.

A Sales Process contains the Stages an Opportunity follows
through its sales cycle.

In order to create Sales Process, follow the below steps

1. Go to App Setup –> Customize –> Opportunity –> Sales Processes.

2. Click “New” button.

3. Enter the Sales Process name and click “Save” button.

 4. Select the required Stage values and click “Save” button.

5. Now create a Record Type.

6. Select the Sales process in Record Type creation and save the Record Type.

Output: