On1 saves its sidecars with *.on1 and *xmp extensions. The photo edits you have made are stored in the *.on1 file, and the image's metadata is stored in the *.xmp file.

For example, if you start with a raw file named XYZ.raw, edit it, and then export it as a jpeg, you will end up with XYZ.jpg, XYZ.on1, XYZ.xmp and the original XYZ.raw.

To add a bit more confusion:

If your editing process involves using 2 images, for example you start with XYZ.raw and then add another layer using an image named ABC.raw, you will also generate a sidecar file which will be named either XYZ.onphoto or ABC.onphoto.

Are you talking about the file names? The software appends ON1 to output file names by default (although you can change that), presumably so you will know which software you used to create that output file. ON1 is a non destructive raw processor. When you are editing your original files, any edits are stored in side car files using a .xmp extension with the same name as your original files. Do not delete them. To have those edits permanently applied to an image you must export your edited files. ON1 permanently bakes in those edits from the .xmp files into your output file during export. Based on your question I assume you are a fairly new user to ON1. I strongly suggest you look at as many online training videos as you can.

This is were I get Lost..... You are saving to Computer???? My approach, I export all of my card into On1. These are placed inside a folder, These are Saved in On1 library. I then select photo from browse menu, click the edit menu and then edit from there. This should be saved as your Only photo. You will not have two copies, but only one with all the edits. If you are saving to computer, where are you saving the photos. In a separate folder, on your desk top, into a different editing software???? If you take a look at the link I sent, you will find easy to understand tutorials on On1. Either the first or second video tells you how to either save photos to On1 or how to edit them from a different location, like Lightroom, aperture, photos, etc.....