Using Annotations in Packages
The SSIS Designer provides annotations, which you can use to make packages self-documenting and easier to understand and maintain. You can add annotations to the control flow, data flow, and event handler design surfaces of SSIS Designer. You can also use annotations in the Data Source View Designer to document the tables and relationships in a data source view. The annotations can contain any type of text, and they are useful for adding labels, comments, and other descriptive information to a package and a data source view. Annotations are a design-time feature only. For example, they are not written to logs.
When you save the package, SSIS Designer saves the annotations in the package.