Late last year, Microsoft announced it was working on an all-in-one office app for iOS and Android. It appears the iOS version is in the process of rolling out.
The new app brings Word, Excel and PowerPoint into a single app, improving and simplifying worksflows. Microsoft still intends to offer the individual apps, especially for users that may only need one or two. For users who rely on the entire suite, however, the new app will have some nice improvements and save space.
The new app is on the App Store although, at time of writing, only an iPhone-optimized version was available. When running it on an iPad, it recommends downloading an iPadOS app, although only the existing, stand-alone apps are available. Hopefully the iPadOS version is coming and has just not hit the App Store yet. Given that Office works best on an iPad, it seems unlikely Microsoft would fail to release an iPadOS-optimized version.
In any case, once (if) both apps are fully available, Office will be a nice addition to the Microsoft family of apps, giving customers yet another option.