Apparently its very easy to enroll Azure Joined devices into intune, No loss of data and can be easily managed like any other device afterwards.
An Azure joined devices means the user is logging into his device with Microsoft 365 credentials (email and password) or a pincode if you have Windows Hello configured in your tenant.
This also means that under Settings > Accounts > Access work or School the user is listed in there saying Connected to <Tenant Name> Entra ID
All you need to do to enroll the device into Intune is the following
- Start Powershell with administrator rights
- Type in the following command
Deviceenroller /c /Autoenrollmdm - It could take a few minutes to maybe an hour for the device to be fully enrolled in Intune. Just check the list of devices or the device itself if any required apps are installed, usually the first thing you see is the Microsoft Intune Management Extention