What's the cleanest way to integrate apps across multiple devices?
Enabling automatic App Store downloads on all devices solves this issue for devices that use the same AppleID for App Store. 


macOS this is in the preferences for the App Store App
iOS this is in the settings app under Apple ID > iTunes &amp; App Store


The general case is solved only when you package and script app installs with an MDM framework like JAMF Now. It’s a lot of work to start packaging your apps or manage installers, so most groups don’t fully manage all apps until they have 50 to 100 Macs, but the technology is there to do this on macOS and iOS. There are even comprehensive books on packaging such as Armin Briegel’s