What is the equivalent procedure for ios to creating an .apk file for android?

For several very small internal apps, I’ve had good success with Meteor + Cordova creating an .apk file which I can then easily install on any Android device.

What is the equivalent procedure for ios ?

As this is an app for myself and a few others, I’m not really keen on paying 100 dollars for an apple developer account… is this the only way ?

You only need a license once you decide to publish on the App Store, messing around is free.
You need Xcode to build apps, which only runs on OS X, so you need either a Mac or a VM.
The procedure is more or less the same as for Android, just read the Meteor Mobile guide.