You need to pass the AZ-104 certification exam to get an Azure Administrator Certification. For that, you need to learn the following concepts and I have mentioned the required topics along with the weightage of each topic in AZ-104 exam:
Managing Azure identities and Governance (15-20%)
Implementing and managing storage (10-15%)
Deploying and Managing Azure compute resources (25- 30%)
Configuring and managing virtual networks (30-35%)
Monitoring and backing up Azure resources (10-15%)
If you are preparing for Azure administrator certification, I would recommend this course on Azure Certification by Intellipaat that offers Instructor-led training, hands-on exercises, and job assistance.
Also, watch this video on Azure: