Is paid Apple Developer Program subscription required to distribute test IPA file?
So as a new iOS developer i found three way for building and distributing app.


For app store distribution normal developer license can work. 
For in House apps you can buy enterprise edition license. With this you
can distribute app via MDM and diawi when you want to
distribute .ipa file of your app.
If you have limited in house
users and have physical access to those devices you can directly
install app via xcode in the device.