If I use iCloud in outlook do I need the outlook app on iPhone

<p>You mean Outlook desktop on Windows or Mac? You shouldn't be restricted on using a different app on mobile.</p><p>Given Apple's restrictive App policies, I would guess that Outlook App on iPhone will not be as good an experience on the iPhone as the native apps, because it can't be the default app for mail, contacts and calendar. </p><p>I haven't used an iPhone for a few years, so I don't know just how good/bad the experience is, but the native apps will probably be easier to use, purely because they are the (only) defaults, when sending emails or adding contacts from other apps.</p>