Microsoft is going fast, really fast with their developments on their Azure platform. As a result you, the Azure Administrator, needs to keep learning all that new stuff. That's nice and all, but at a certain point you maybe want to have some proof of excellence of what you've learned. For this, you can take and pass an exam and show to your boss, coworkers or your cat that you know your shit.

But as soon you've taken that exam on something Azure related, it's already outdated. Thanks Microsoft, for those fast development cycles. ;-) But, there's a new kid on the block now; the Microsoft Azure Administrator certification. You can read up all on this here: https://www.microsoft.com/en-us/learning/community-blog-post.aspx?BlogId=8&Id=375147

Basically it boils down to this; if you didn't took 70-533 in the past, you need to take AZ-100 & AZ-101. If you already have 70-533, you only need AZ-102. After passing it, you can call yourself Microsoft Azure Administrator.

Some more info here:

And important to note, if you're fast with booking, then there's a big discount!