# Components Components are the core of MJML. A component is an abstraction of a more complex email-responsive HTML layout. It exposes attributes, enabling you to interact with the final component visual aspect. MJML comes out of the box with a set of standard components to help you build easily your first templates without having to reinvent the wheel. For instance, the `mj-button` component is, on the inside, a complex HTML layout: ``` html Hello There!
Hello There!
``` ## mjml A MJML document starts with a `` tag, it can contain only `mj-head` and `mj-body` tags. Both have the same purpose of `head` and `body` in a HTML document. attribute | unit | description | default value ----------|------|-------------|--------------- owa | string | if set to "desktop", will force desktop display on outlook. Otherwise outlook will display mobile version since it ignores media queries | none lang | string | used as `` attribute | none ## mj-head mj-head contains head components, related to the document such as style and meta elements (see [head components](#standard-head-components)).