There are so many! The pen is completely mightier than the sword on an historical scale and usually on an everyday scale. Everything from the Declaration of Independence to the U.S. Constitution to the Louisiana Purchase (add 1,000,000 USA examples here), the documents President Obama signed just recently confirming him in his second role in the presidency, and the documents from which he read his state of the union address. Birth certificates and death certificates for each individual; everyone's home deeds and car titles, the driver's license, the green card, the passport (opening our minds to other cultures). Degrees, diplomas, and certificates validating someone's book-knowledge, and the resume summarizing it for future employment. The gold record that we send with space exploration probes so that anyone finding our probe will know about us. The scripts of a different nature upon which Mozart and Beethoven (and thousands of other composers) wrote their masterpieces for formal/royal occasions during which important treaties were likely signed (even if the treaty was a marriage license). The phenomena that IKEA documents are horrible yet we still buy their stuff and somehow assemble it. My examples may seem pedantic at first, but look: the birth certificate of George Washington forever in our minds locks a nametag on a select individual who did great things. And I would be totally remiss if I didn't mention all of the tomes upon which religions worldwide have been based (I won't list them to avoid offense by inadvertantly omitting one). Modern currency also contains text that assigns value to the pieces of paper. Articles of Incorporation, patents, copyrights. Prescriptions, grocery lists, recipes.
Virtually everything written that is read by someone makes a difference in some way, great or small, and the sums of those great and small things form raised awareness and social change. For example, the recipe for making hydraulic cement was lost during the great fire in the Alexandria library, and it was another (millenia to 1500 years?) before someone again figured out how to make it from scratch. Think of how many important and stately occasions were graced and celebrated with the "Ode to Joy", how many brides' and grooms' blood ran a little faster upon hearing "Here comes the bride".
Of course, written text can also be used for horrible purposes, such as tearing apart nations, breaking agreements, starting wars, bullying, teasing, hating, et al.