Add additional input for the client credentials flow

I am using the Swagger for the first time and my API uses the client credentials grant type with an additional "email" field. How would I go about configuring Swagger to achieve this? I have this so far: 

components:
schemas: {}
securitySchemes:
application:
type: oauth2
flows:
clientCredentials:
tokenUrl: 'http://example.com/oauth/token'
scopes:
write: allows modifying resources
read: allows reading resources

Thanks in advance