add apm data types

Author: mdbirnstiehl

solutions/observability/apps/learn-about-application-data-types.md

@@ -4,11 +4,23 @@ mapped_urls:
   - https://www.elastic.co/guide/en/serverless/current/observability-apm-data-types.html
 ---
 
-# Learn about application data types
+# Application data types [observability-apm-data-types]
 
-% What needs to be done: Align serverless/stateful
+Elastic APM agents capture different types of information from within their instrumented applications. These are known as events, and can be spans, transactions, traces, errors, or metrics.
 
-% Use migrated content from existing pages that map to this page:
+Elastic APM helps you see what happens from start to finish when a request is made to an application:
 
-% - [ ] ./raw-migrated-files/observability-docs/observability/apm-data-model.md
-% - [ ] ./raw-migrated-files/docs-content/serverless/observability-apm-data-types.md
+* [**Spans**](../../../solutions/observability/apps/spans.md): A span contain information about the execution of a specific code path. They are the building blocks of *transactions* and *traces*.
+* [**Transactions**](../../../solutions/observability/apps/transactions.md): A transaction describes an event captured by an Elastic APM agent instrumenting a service. A transaction is technically a type of span that has additional attributes associated with it and often contains multiple child *spans*. You can think of transactions as the highest level of work you’re measuring within a service.
+* [**Traces**](../../../solutions/observability/apps/traces.md#apm-distributed-tracing): A trace is a group of *transactions* and *spans* with a common root. Each trace tracks the entirety of a single request. When a trace travels through multiple services, it is known as a *distributed trace*.
+
+:::{image} ../../../images/observability-spans-transactions-and-traces.png
+:alt: Diagram illustrating the relationship between spans
+:::
+
+In addition to the building blocks of traces, Elastic APM agents also capture:
+
+* [**Errors**](../../../solutions/observability/apps/errors.md): An error is created when something goes wrong with a request to an application. This event contains information to help you determine where and why an error occurred, often including in which *transaction* the error occurred.
+* [**Metrics**](../../../solutions/observability/apps/metrics.md): Metrics measure the state of a system by gathering information on a regular interval.
+
+Events can contain additional [metadata](../../../solutions/observability/apps/metadata.md) which further enriches your data.