Set custom header on webhook request

Set custom header on webhook request

Hello everyone,

I am playing around with ZohoDesk webhooks and I would like to know if it possible to add one or many custom header(s) on the request.
The webhook is connected to my API which requires a oauth2 token (bearer). I am currently unable to set the token to the POST request. 

I would be glad to hear any solution from you. 

Regards,