Thank you for your replies.
Here is what I did when configuring SD-WAN to configure a dedicated link to Office365 traffic.
1. Configured SDWAN Zone
2. Added WAN interfaces as members to SDWAN Zone.
3. Configured SLA.
4. Configured SDWAN rule with Office365 applications control.
5. Configured security policy adding SDWAN interface for outgoing interface.( Did not add anything in the application section in the policy i.e. allowed all )
Then I checked whether set up is working. But it still did not work since I could browse all the traffic. Then I added Office365 application control to security policy , then I wasn't able to access login.microsoftonline.com or any other website.
Please note when I tried to add a default route with SDWAN interface it did not work.
Please let me know, where could I have gone wrong. I am doing these configurations in my laptop using a simulator.