Extended Security Updates are critical if you want to continue safely running Windows Server workloads on versions that are out of support. They’re free for customers running Windows Server in Azure and available to purchase through an EA for on-premises workloads.
Servers in Azure receive ESUs by default, and there’s an excellent article here (https://bit.ly/3LTxdrS) on how it works for on-premises servers where it’s not automatic and you need to register your servers.
If you’re running Azure Stack HCI then ESUs are free but you need to turn on Azure Benefits – and this article (https://bit.ly/3M4gX7s) is useful for explaining that process. If you’re new to Extended Security Updates, then this article is a good place to start: https://bit.ly/3NFed1C.