Initiating iPhone call from windows 10

No, you cannot do it.

There used to be an application for Apple OSX laptops and desktops called Dialectic which could do this with a paired iPhone but as far as I'm aware there has never been and is no such an application for Windows 10.

https://getcallbridge.com/ - these guys have something that works (via a push notification) but they want a 6€ monthly fee which I think is over the top

That is slightly different .. what is happening there is you COPY data to the clipboard on the PC or within Chrome .. it then sends that to their server which in turn creates a NOTIFICATION which the app (you have to install their app on the iPhone) can pickup and that can trigger a phone call.

All the numbers are passing through getcallbridge.com system in order for their app to trigger the Notification which in turn allows it to pass the data to the phone app on iOS.

There is no application which can communicate and initiate a call on an iPhone without an Internet connection and the data being routed through a 3rd party server.

Ah ok - actually that would suffice - i guess I dont need to initiate per se. Would you know of another solution that allows what callbridge does? but not at 6€ a month!

I'm not aware but others may be able to contribute.  

To be honest the VOIP solutions such as Viber/Skype etc with call credit are the more common solution to dialing landlines and mobiles from a dekstop/laptop with Windows 10 rather than trying to pass the number to an iPhone.