You could save to a folder on your computer or copy to an SD card or thumb drive to hand off to your client.
If your originals are raw files you may wish to save full resolution jpegs otherwise use an appropriate custom size.
It is also possible to set up a web share which others can download as a zip file.
I usually do put the files on a thumb drive. Thought maybe I could get lucky and I could have thee clients just save them to their computer and cut out my cost in thumb drives and stamps. Any suggestions on web shares?