How to choose the right category of Virtual Machine based on application requirement?

Azure offers six different categories or groups of virtual machine types to cover various scenarios ranging from Dev / test to complex high performance computing. Choosing the right VM type based on the solution scenario will help partner to optimize the performance for customers and save cost.

Refer to the page here for the list of virtual machines types with their suitability marked against each category. One can choose to switch from one type to another based on availability of the offering in the region.