You can use the built-in app credential activity report: https://learn.microsoft.com/en-us/entra/identity/monitoring-health/concept-usage-insights-report?tabs=microsoft-entra-admin-center#application-credential-activity-preview
Or the expiring credentials Entra ID "recommendation": https://learn.microsoft.com/en-us/entra/identity/monitoring-health/overview-recommendations#recommendation-availability-and-license-requirements
Or you can build your own report based on PowerShell or the Graph API. I have some samples here: https://www.michev.info/blog/post/5940/reporting-on-entra-id-application-registrations