For the time being the service is only available to enterprise customers as part of Microsoft Defender to ATP. Who uses the Antivirus in his company, can access the App via a login to the Preview program for the employees available. The Android App has a Phishing-protection, a Blocklist for unwanted and dangerous Websites, as well as a Malware Scanner, which blocks the Installation of insecure Apps. In addition, access blockages for documents set up to be viewed, for example, only of a certain group of people.
For Android Google offers with the Play Protect is a virus scanner that is performing but in the Tests very well. Anyone who wants to better protection, use a virus protection from a third party. The best virus scanner for Android, we have looked at in the CHIP-Test. What Microsoft is planning for private clients with Windows Defender for Android is not yet known.