How to move apps from device storage to iCloud storage

Apps cannot be stored on iCloud but the following option may help. See below from How to check the storage on your iPhone, iPad, and iPod touch - Apple Support

Use your device to check its storage

Go to Settings > General > [Device] Storage. You might see a list of recommendations for optimizing your device's storage, followed by a list of installed apps and the amount of storage each one uses. Tap an app's name for more information about its storage. Cached data and temporary data might not be counted as usage.

In the detailed view you can:

• Offload the app, which frees up storage used by the app, but keeps its documents and data.
• Delete the app, which removes the app and its related data.
• Depending on the app, you might be able to delete some of its documents and data.

If your device is almost full and can't free up space, you might get a Storage Almost Full alert. If you see this alert, you should check the storage recommendations or you need to offload some less-used content like videos and apps.