add a content type to a SharePoint document library

Content types allow you to store documents of different types in the same SharePoint document library. For example, you can use content types to define multiple document templates on a SharePoint document library.
Adding a content type to a document library in SharePoint is a 2-step process:

1. Enable the management of content types on the document library.
2. Add the content type to the document library.

Enabling management of content types on a document library

By default, content types are disabled on document libraries in SharePoint. So before you can add a content type to a document library, you must enable management of content types on that document library.
To enable management of content types on a SharePoint document library:

1. In SharePoint, go to the document library on which you want to enable management of content types.
2. On the Settings menu, click Document Library Settings.
3. On the Customize document library page under General Settings, click Advanced settings.
4. On the Document Library Advanced Settings page, select Yes under Allow management of content types?, and click OK.

Figure 1. Allow management of content types on a SharePoint document library.

Adding a content type to a SharePoint document library

Once you’ve enabled the management of content types on a SharePoint document library, a Content Types section appears on the Customize document library page.

Figure 2. Content Types section on the Customize document library page.
Now you can click Add from existing site content types under the Content Types section on theCustomize document library page to add a content type to the SharePoint document library.