Creating a personal use iPad app (not published)

I want to create an iPad app for my uncles small business, one thats specific to his business and how its run and is as simple to use as possible for his workers who use these iPads out and about. I also want to be able to access the information on the app from a macbook version of the app to be able to see everything and print out the lists that will be filled out every month by the workers. I'm not 100% sure because I've never created an app like this or any app in general, but would this require creating a server for the iPads to connect to for me to access the information on the laptop. And also do I have to go through the process of getting a developers license or is there a way around it and to just have the app on the company iPads since I wouldn't want to publish it for public use anyway. And for anyone with experience creating this sort of thing, having an iPad app communicate with a macbook app, sharing the data, how difficult on a scale of 1 to 10 do you think this would be. I would be using xcode 11 and coding in swift to try to accomplish this but if anyone can recommend something better for the task it would be appreciated.