An asphalt driveway must be sealed. Especially a new drive needs to be sealed 3 to 6 months after installation, but better late than never. Without sealing, the top aggregate will begin to loosen and the driveway will eventually lose integrity. The sealant also prevents water penetration preventing weeds and breakup.
Unfortuanately, asphalt sealing is one of the greatest contractor scams of all time. There are companies that use top notch materials and properly apply the materials, and there are bunches of frauds that solicit business then disappear. Buyer beware. Use a local company with an established reputation, license and references.
You can do this yourself. Buy the highest quality asphalt sealer you can find. It is sold in 5-gallon buckets at hardware and HI stores. Buy the better stuff, not the cheap. You will save about 2/3 the cost of professional installation. Expect 300 to 500 square feed coverage per bucket (read the label). You will need a broom / squeegee sold the same place you buy materials. Wear old shoes, have fun.