Each area has its own activity log (see the Activity logs category). The admin logs sit above those — they cover the things that aren't tied to a single area:
User sign-ins / outs.
Invitations sent, accepted, revoked.
Role changes.
Branding / SSO config changes.
Workflow activations and configuration changes.
Searching
Same filters as per-area logs: by user, by action, by time. Cross-area searches use the realm-wide log view in admin → Logs.