Content type - field type - Select list: Add options: Existing content on the website
Assuming you are using Drupal 7, I think you need the Entity Reference module.

This module provides a field that you can add to your content type peaches and provides the requested widget that allows you to select from all the bananas nodes your website has. When outputting the peaches node, the standard formatter (that the Entity Reference module offers) creates a link using the selected bananas node's title.