Use Ctrl/Cmd+A to select all of the files (or Shift to select everything between two points). Go to Export>Export Location>Specific Folder. Choose the format you would like and the quality (if applicable) and hit Export. Once that has finished, you have completed your task.
If you just want to save the edits, this is done automatically to the LR catalog. LR never touches the originals, but saves the edits as metadata to the catalog.
If you need to use these photos for a particular purpose, follow Benjamins advice and export. If not, you don't need to do anything.