I store my choreo for dances in Word documents (one document per dance) that I have online in the online file storage/sharing app Dropbox.
I use Word and Dropbox because these are commonly available programs that will be available and supported for decades.
I avoid using specialized dance programs because they have a tendency to stop being supported after a period of time, and I don't want to get into a situation where I need to recreate a new electronic library of choreo and deal with potentially problematic import/export/format issues.
I set the Dropbox directories so that they are stored offline on my phone and iPad, so I do not need an internet connection at the dance.
I always have 2 choreo sources with me (a phone and an iPad) in case something goes wrong with one of them.
I also frequently take the program for the evening and take screen shots of the individual dances--in sequence--so that they will be in the Photos app in addition to Dropbox.
I usually call from the Photos app, but I can consult Dropbox if I need to go off program.
The fact the choreo is stored in Word docs allows me to easily edit them to add notes, change things, etc., over time.
Hope this helps!
Jimmy Akin
San Diego