From reading some of the old posts in the UserVoice thread states:
There are a quite a few complications as related to licensing, partitioning, and security issues with windows servers.
https://digitalocean.uservoice.com/forums/136585-digitalocean/suggestions/2536799-support-windows-server

@hansen Thanks for that share.

@FrostGamers, on top of what hansen said, Windows isn’t the go to OS for website hosting. If you are more familiar with Windows, I’d suggest looking elsewhere or, you could learn Linux. :D

Hello,

At this time we do not have native support for Windows OSs on Droplets. You may be able to achieve this however by creating your own custom Windows ISO image and then using that when creating your Droplet.

Currently, DigitalOcean only allows the deployment of Linux based OS’s.

NOTE: This is not natively supported on the platform (choosing a Windows OS when you deploy your droplet).

We’d recommend that you add your vote to the Windows Server idea on our Product Ideas Board as well as comment your use-case there so that our teams can better understand your needs.

https://ideas.digitalocean.com/ideas/DO-I-2872

Hope that helps!

Regards,
Alex