Wax forms thin transparent layer over the paint that covers minor scratches
Waxing gives your car natural shine and helps to protect the paint from harsh environment. When applied, the wax forms a thin transparent layer over the car paint. This layer covers minor scratches, stone chips and other damages, making them less visible. The wax also 'seals' the paint, preventing water from contacting the bare metal exposed in deep chips and scratches, slowing down the corrosion process.
For best results, a wax needs to be reapplied regularly - none of the available car wax products will stay permanently on your car. From my observations, a good-quality car wax stays on the car for about three-four months, so if you wax your car at least every three months using a good product, you'll be OK.
If a car hasn't been waxed in a very long time, first, it make sense to take it to a local detailing shop, or you can visit your dealer (e.g. for an oil change) and ask for one of those detailing packages they offer. What they do, they buff the car with electrical buffer using special polishing compound containing a mild abrasive to remove light scratches, hard stains and other impurities on the paint, then they wax it. After your car has been detailed, you can simply reapply wax every three months or so to keep it shiny.
To wax your car you will need some good quality wax (e.g. Carnauba wax), a small soft sponge and a clean soft cloth towel. Your car must be very clean and dry. I usually wax my car right after washing it at the coin car wash; the whole process of washing, drying and waxing takes about an hour.
Make sure to choose the right product - you need the wax with no abrasives. Read the directions on the package for any specific product and test it on some small area first.
Park your car somewhere in the shadow - usually it works better when the car surface is cool to the touch. Work on one section at the time, for example, on one fender or door.
If you use liquid wax, shake the bottle well before use. Apply small amount of wax to the sponge and spread it evenly on one section of the car. It's good idea to start from the top and do the bottom panels last because there is always some dirt left at the bottom.
You want to make a thin, even layer of wax. Try not to touch the surfaces like black window trim, rubber door seals and black matte plastic - the wax will leave white stains on them. Work on one section at the time.
Allow the wax to haze (takes about a minute or two). Then buff it to a perfect shine with clean soft towel, rotating it frequently - clean part of the towel works best.
After the whole car is done, clean the wax from matte unpainted surfaces (e.g. plastic mouldings, unpainted bumper, rubber door seals). Window spray cleaner will work well for this purpose.
I recommend to wax your car regularly, for example, once in every three months. I tried many products and non of them stays permanently. Any car wax needs to be reapplied regularly Source