I have a Singer 6268. The feed dogs are in the down postion and I cannot find where to raise them!
Here's a link to the Singer website free download of the manual for your sewing machine:
As near as I can work out from a quick scan of the manual - your machine doesn't have a raise-lower feature for the feed dogs. The machine comes with a snap-on feed dog cover that stops the feed dogs from coming into contact with your fabric. Is that on the machine? (see the pages in the manual about 'free motion embroidery')
If the cover plate isn't on the machine and your feed dogs are lower than the throat of the machine - you need to take your machine to a Singer qualified repair tech. This isn't a home fix.