Company Portal - (iPhone) Add Company Portal, Microsoft Authenticator, Slack, Outlook to your phone
About
This guide shows you how to add Company Portal, Microsoft Authenticator, Slack and Outlook to your iPhone.
First:
If you are in the office when doing this, disconnect from 5G, and use the Guest Network instead.
1. Install Microsoft Authenticator
- Open the App Store and search for Microsoft Authenticator.
- Tap the cloud button to install it.
2. Install Intune Company Portal
- Open the App Store and search for Intune Company Portal.
- Tap the cloud button to install it.
3. Set up Microsoft Authenticator
- Open Microsoft Authenticator and tap Accept.
- Tap Continue. You do not need to tick the box.
- Tap Add work or school account.
- Tap Next.
- Tap Sign in.
- Choose I can’t use my Microsoft Authenticator app right now.
- Choose Text +XX XXXXXXXX (your phone number).
- You receive an SMS. Type in the code from the SMS and tap Verify.
- Tap Allow or Don’t Allow (notifications). It is up to you.
- Tap Continue.
And you are done! 
4. Set up Company Portal
- Open Intune Company Portal and tap Sign in.
- Tap Unlock.
- Enter your phone unlock code, or use your fingerprint or face if that is turned on.
- Tap the account you want to connect the Company Portal to.
- Tap OK. If you are asked about notifications, choose Allow or Don’t Allow.
- Tap Begin.
- Choose Can, then tap Continue.
- Tap Continue.
Important: if you have a YubiKey, there is one extra step here. You need to use your YubiKey code at this point. If you do not have a YubiKey, skip this note and carry on with the next step.
- Tap Allow.
- Wait a little while. When the profile has been downloaded, tap Close. Then tap Continue in the next popup.
- A new page appears. Tap Continue.
Important: at this point you HAVE to follow the tutorial shown on your screen.
- Follow the tutorial on your screen.
- Tap Enroll in Neonomics.
- Tap Enroll my phone.
- Enter your phone unlock code, or use your fingerprint or face again.
Important: in the next step, your phone asks for your Apple ID password, NOT your Neonomics sign-in password. They might be the same, but it is worth checking, just in case they are not. 😄
- Sign in with your Neonomics Apple ID username and password.
- Authenticate. This is done either with your phone number or with the Microsoft Authenticator app.
- Wait. When asked, choose what you prefer about restoring data or not.
- Tap Continue.
- Wait again.
- Tap Done.
Congratulations, you are done! 
Source:
Microsoft’s guide for enrolling an iOS device with Company Portal: https://learn.microsoft.com/en-us/mem/intune/user-help/enroll-your-device-in-intune-ios