I've just finished developing my application with ionic,I'm working on windows,i run :
ionic run android
You cannot run iOS unless you are on Mac OSX.
You can't build the .ipa package in your Windows machine because you'll need XCode for that.
but still you need a machine with ios installed, this is just about certificate generation. Also the final version of your app, must be uploaded with XCode.
So a possible solution is to install a macOS virtual machine on windows base pc.
Also you can get virtual mac machine. Have a look at these: