Setup a virtual machine in Azure and install Veeam onto that - then setup some storage connected to that VM for your Veeam Backups to copy to. Setup "backup copy jobs" from on premise to you Azure virtual machine. Take a loop at the calculator for Azure pricing: https://azure.microsoft.com/en-gb/pricing/calculator/
Or investigate "Veeam Cloud Connect" as an option: https://www.veeam.com/cloud-connect.html