This appendix is a supplement to the report "Possible Ways of Increasing College Access Among Adults from Underserved Backgrounds: A Study of College Transition Text-Based Messaging." It provides additional information about the study of Text Ed--the messaging strategy evaluated for its ability to increase college enrollment and Free Application for Federal Student Aid completion rates among clients of Education Opportunity Centers. This includes details about the Text Ed messages, how the study was designed and conducted, detailed impact and implementation analyses, and exploratory analyses to further elucidate the findings and suggest avenues for future study. The content of the appendix is referenced as applicable within the main report. This document presents the following four appendixes that accompany the study: (1) Additional Details on Text Ed; (2) Additional Information About How the Study was Designed and Implemented; (3) Supplemental Tables for the Impact Analysis; and (4) Detailed Implementation Analysis. [For the full Evaluation Report, see ED628025. For the Study Highlights, see ED628026.]