The Azure Activity Log is a subscription log that provides insight into subscription-level events that have occurred in Azure. This includes a range of data, from Azure Resource Manager operational data to updates on Service Health events. You may want to Archive the Azure Activity Log if you want to retain your Activity Log longer than 90 days (with full control over the retention policy) for audit, static analysis, or backup. In this post, I'll show you now to archive it with a couple of clicks.
In the portal, search for the Activity Log service. Now click on the Export button as shown below:
Select a Subscription, Region and place a checkmark in the Export to an Azure Storage Account. Now use the slider to select a number of days (0 to 365) for which Activity Log events should be kept in your storage account. You can may also select 0 to save it indefinitely. Now click Save.
Now your logs are safe and sound for the time you specified.