Do I have to buy the upgrade to edit?

Downloaded an RTF from dropbox and selected it. Displays but could not edit it. tapping the screen does not bring up a keyboard. Do I have to buy the upgrade to edit? I select the documents > button. App crashes. Please address. Do I need help to use what should be a simple app? Need a manual?

Umarekawaru about TextEditor : Rich Text Editor, v8.1