You need to pass one or more exams (tests) to earn a Certification. When you look at the details page for a specific certification, it will list the required prerequisite exam(s) and/or certification(s) needed to earn that certification.
For example, to earn Microsoft Certified: Azure Administrator Associate certification, you need to pass exam AZ-104: Microsoft Azure Administrator. Only one exam needed to earn the certification, no other prerequisites.
Second example, to earn Microsoft Certified: Azure Solutions Architect Expert certification, you need to have Microsoft Certified: Azure Administrator Associate certification PLUS pass exam AZ-305 Designing Microsoft Azure Infrastructure Solutions. Effectively, you need to pass two exams to earn the certification.
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