Which token should I send while calling a firebase function from react app ? session token/ oauth access token?

I am trying to create a react application. I am trying to get data from my board and storing it on firebase firestore.

My firebase function work perfectly well. I want to implement authorization middleware to this firebase-cloud-function’. For this purpose, I need to send a token along with authorization header in the request. But which token should I send? (session token ? obtained from monday.get(‘sessiontoken’) or oauth access token with no expiration time ??)