What is observability and How to practice observability?

What is observability?---- Observability is basically system property that allow us to take information of each event, log , metric ,trace and then show it as visual board so we can track each and every activity (infra, app, network etc) and also make predication for future on the basis of information.

How to practice observability?---- To practice observability we can setup the system (like datadog) that provide insight of each activity , log, trace ,metrics and get related information for past, present or even future (hypothetical predication).

What are the datatypes we need to collection to setup observability-- Metrics, event, Logs, Trace