There are a lot of different VM sizes available to choose from in Azure. Note that it is important to know what options there are from a design perspective, because choosing the wrong VM size can have a negative impact on the performance of your VM, or your application installed on the VM. Choosing between the different available options will also have a huge effect on the overall costs. For example, if your company or client wants to reduce costs by migrating data centers to Azure, choosing your VMs wisely will either make your project a success or a failure.
Azure VMs are organized into machine series, starting with the A-series, which are VMs mainly used for general purposes. There are also VM sizes that are optimized for compute, memory, storage, and GPU, as well as high-performance compute VMs. All of the available series and sizes are explained in more detail in the following section.