Well, I had the same doubt and i used to messed myself with several answer. Then i sat for a while and went through the apple docs.
Here is some notes from their docs
To develop and deploy custom apps for iOS,
First register for the iOS Developer Enterprise Program at:developer.apple.com/programs/ios/enterprise
Once you register,
you can request a developer certificate and developer provisioning profile.
You use these during development to build and test your app.
The development provisioning profile allows apps signed with your developer certificate to run on registered devices. You create the developer provisioning profile at the iOS Provisioning Portal.
Well that was for build and test the app.
Now for the distribution
There are two options :
In-House and Ad-Hoc
Ad-Hoc :
The ad-hoc profile expires after 3 months
and specifies which devices (by device ID)
can run development builds of your app. You distribute your developer signed build, and the development provisioning profile, to your app team and testers.
In-House :
Now, when you feel that your app is ready to distribute to the real user after getting all the testing done. You can use build your app In-House profile. See the image to get more details
The only difference is you do not need to add the device ID for the In-house distribution provisioning profile.
I use the testflightapp.com to distribute the app with In-House profile. Its all your choice you can use your own wireframe.
I know you do not need to submit your app to the app store for review. Its not required but my client always want so, I submit our enterprise app to the app store for just review not for publish.
I will recommend you to go through this docs
Happy coding :)