Many of the clients above support something like certbot's webroot plugin, which is web server-agnostic and works by simply putting a verification file in your

Many of the clients above support something like certbot's webroot plugin, which is web server-agnostic and works by simply putting a verification file in your webroot and serving that to Let's Encrypt's validation server. Also: As far as I know, IIS is included with any Windows version (definitely any version of Windows Server).