You can’t have it all, and this is true even for the best things in life. It’s possible to schedule automatic shutdowns of VMs in Azure (one of the ways to cut Azure costs). But you can’t use the same Azure Portal to schedule their automatic boot-up the same way. A way out of it is to use PowerShell, however, there’s another trick you might like better.
Read the article by Nicolas Prigent, a three-time Microsoft MVP, about using Azure Logic Apps to automatically start your VMs at whatever time you specify.