Azure VMs are available in different series, with each series demanding different specifications in order to fulfil the scenarios you want to deploy:

• A-series: This series is most commonly used in development and test scenarios
• D-series: This series has a fast CPU and solid-state drive (SSD) disks, and is most commonly used for general-purpose computing, such as relational databases, and every application that requires high IOPs
• F-series: This series targets applications that require intensive compute power, such as web servers
• G-series: This series targets applications that require high memory and fast storage, such as ERP, and SAP solutions
• H-series: This series has very high compute capabilities, and might fit in scenarios that require high performance, such as analytics
• L-series: This series is dedicated to applications that require low latency, high throughput, high IOPs, and large size disks, such as NoSQL databases
• N-series: This series has high GPU capabilities, and fits scenarios such as video editing, graphics rendering, and so on
• B-series: This series provides the lowest cost of any exciting size with flexible CPU usage; it mainly targets web servers, small databases, and development/test environments
• M-series: This series provides the biggest VM sizes in Azure at the time of writing; this series is a better fit for large in-memory workloads, such as SAP HANA and SQL Hekaton.