You can change the configuration(cores, RAM, storage) of your current virtual machine under size menu. Azure provides many options to change the configuration based on your requirements.
Step 1. Login into your Microsoft Azure account.
Step 2. Open your Virtual Server which you want to resize.
Step 3.Click on Size option under the settings in the service panel of the page & Select New size for your virtual machine as per your requirement.As for now I am going to select D2_V2 standard.Now click on Select button to continue.
Note: Wait for few minutes because resizing process will take few minutes.
Step 4. Now click on Overview in the service panel of the page & check your Virtual Machine new size under Size column.