Hi HusseinAkberali,
Do you mean URL use to sign in to Outlook Web App? If yes, then open IE web browser on surface pro 2/Windows phone, or if it's already open, open a New tab.
Use the following URLs to access OWA:
1. http://mail.office365.com/
2. http://outlook.com/yourdomain.com
For more information:
What URL do I use to sign in to Outlook Web App?
Supported browsers for Outlook Web App
Best regards,
Shyamal