I have developed an 'App for Office' (for Word) that runs as a task-pane app. When I open a Word Document, I can add my app and let it run on the task-pane.
How can I run my app when I am on my iPhone/iPad and using the iOS version of Microsoft Word? I wasn't able to find where I can add my app into the document.
I am aware this is more of a support question for Microsoft, but Stackoverflow seems to be the best place for now (I couldn't find any relevant StackExchange site).
Store add-ins are definitely supported on IOS in general, but not all add-ins. The developer has to tick a box and provide evidence that the add-in has been tested on IOS for it to be available to users, so the IOS versions of Office will have less add-ins available.
That said, you should be able to see the ones that are available via the Insert menu. Look for Store or My Add-ins under the Insert menu.