Description:
Enable Diagnostic settings for exporting activity logs.
Diagnostic setting are available for each individual resources within a subscription. Settings should be configured for all appropriate resources for your environment.
Rationale:
A diagnostic setting controls how a diagnostic log is exported. By default, logs are retained only for 90 days. Diagnostic settings should be defined so that logs can be exported and stored for a longer duration in order to analyze security activities within an Azure subscription.
From Azure Console
Repeat these step for all resources as needed.