Certificate based authentication for Outlook app on Android & iOS

Hi All,

I have a third-party certificate authority integrated with Intune tenant. 

Outlook app is configured under app configuration policies with Modern Auth as below and not assigned.

Outlook client is deployed for both Android and iOS devices 

The certificate authority is issuing a user certificate for all enrolled devices.

My questions are

1. How can I use the user certificate to maintain the Outlook seamless authentication ( no user name & password prompt)?

For iOS I have created a device configuration policy for Exchange Active sync which has the option for me to select the authentication method as a certificate and I have to select the user certificate. Is this the correct approach for certificate-based authentication?

2. For Android I couldn't create a similar device configuration policy as only Gmail and Ninework are visible under the select app. What would be the approach for Android devices?

Sanka