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You can as long as they have a Microsoft account. Any person from an institution that is using O365 will have a Microsoft account. Additionally, even personal Microsoft accounts can be invited. You can scope their access as appropriate from the subscription as a whole even down to the individual resource level.

Learning

What training options are there to learn more about Azure?

Microsoft offers a free online learning path for Azure Fundamentals. In addition to that, within the Microsoft Learn training options, there are currently 316 related to "Azure".