Azure is the platform developed by Microsoft that provides cloud services to build, develop, deploy, and manage applications. Azure can be used for various applications such as Infrastructure services, Mobile Applications, Web Applications, Cloud Services, Storage, Backup, and Recovery, Data Management, and Media Services. Azure is used to implementing back up and disaster recovery, host and develop mobile and web applications, distribute and supplement active directory, and innovate with IoT industry solutions.
I suggest signing up for this Azure developer certification program by Intellipaat to acquire skills in Azure administration.
You can watch this video on Microsoft Azure to know what is Microsoft Azure used for: