You may want to export your patient list, along with their email addresses and other demographic information.
To do this, go to Reports > Patient Summary.
There is an "export" button on the top of the page that will export your files into a .csv file (spreadsheet). Clicking this will automatically download the file to your hard drive.
If you are using the Safari browser on a Mac computer you may need to click with two fingers on export and select Save Link As.