This document provides an overview of content registration with Crossref. It discusses what types of content can be registered (e.g. journals, books, datasets), how to structure metadata using Crossref XML schema, and how to upload content and metadata using the Crossref deposit form or API. The document also describes how to create Crossref XML files with metadata, persistent identifiers, and references. It outlines the submission and processing workflow, including receiving logs on success or errors.