# Content Types and Structure

In Umbraco, all content is defined by a type. Document Types define the fields on a page, Media Types define the properties of media items, and Member Types define user profiles. This section covers how to create and configure these content types and how to build structure through compositions and relations.

* [Backoffice](/umbraco-cms/18.latest/model-your-content/content-types-and-structure/backoffice.md) - key backoffice concepts: sections, trees, Document Types, Media Types, Data Types, and Property Editors.
* [Data](/umbraco-cms/18.latest/model-your-content/content-types-and-structure/data.md) - define Document Types, create Media Types, configure Data Types, and manage content in the backoffice.
* [Compositions](/umbraco-cms/18.latest/model-your-content/content-types-and-structure/composing.md) - share groups of properties across multiple Document Types using compositions.
* [Relations](/umbraco-cms/18.latest/model-your-content/content-types-and-structure/relations.md) - define and manage relationships between different content entities.


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