I don’t know what kind of frame you have but this should work with all frame types.
I had some scratches on the seat tube of a black carbon Frame that I was able to make good as new again.
I used 600 grit sandpaper on the area that had the scratches; the area I worked on was about 1 inch in diameter. I sanded it down until smooth, masked it off enough around the work area to avoid over spray from getting on to other areas of the frame and bike.
Used Krylon indoor/outdoor flat black on the area. Let dry.
Used Krylon acrylic crystal Clear coat gloss on top of that.
Looks good as new as if scratches never happened.
Good Luck