Template formatting to merge documents

I am looking to find out if I am able to create two templates that look different, but contain the same text without having to copy and paste it over. The text would change depending on what I am writing in it. 

E.g. I have a main document, lets call it a report, and a secondary document which is a summary of parts of the information. I would like that the secondary document, the summary, have the exact same information of some of the boxes of the report. Is there a way I can start typing in the report and it appear in the summary template? 

P.S. It would also be ok if the summary section was just an appendix on the main report. I am just looking for a way to avoid doing a bunch of copy and pasting...