You might get an oil that is in liquid form such as coconut oil when it's above a certain temperature, or you might end up using one that can easily be sprayed like a finish on the hair. It all depends on what you need.
Hair oils is often massaged into the scalp and hair to make it softer, increase moisture, while making it shine. In addition, hair oils can fill in gaps in the cuticle to protect the follicles, and protects the hair from regular wear and tear.
If a person has a dry scalp or hair, they need to use additional oil. It should be massaged in so the scalp doesn't feel as tight. In addition, it is well known that curly hair tends to be dryer so using the oil makes the hair shafts smoother and healthier. The dry scalp or dry hair tend to be this way due to the scalp not producing enough natural oils so it needs a bit of help.
Oil can be used before you wash your hair, during a shower to add a bit of moisture, or before or after you style your hair. I know several people, who apply coconut oil to their hair at least one hour before washing it so their hair doesn't get too dry. It seeps into the hair, moisturizing it and protecting the scalp during the washing step.
Many people also apply oil to their hair, pin it up, and let the steam from a nice warm shower open the cuticles so the oil penetrates the hair. Another way of getting the oil into your hair is to mix some hot oil with conditioner, massage it into your scalp and hair, then sit under a heating cap or dryer for about 20 minutes before washing the mixture out of your hair. It should leave your hair nice and rehydrated.
If you place oil on your hair when it is damp, before you style it or use heat based tools so you can cut down on the frizz once it's dry. In addition, it can help cut down on those fly away strands while providing a smooth finish to the hair. On the other hand, if your hair feels a bit dry, you can apply oil to your hair before you blow it or a bit smoothed over the hair once it's styled so the hair looks healthy and glossy.
When people think of oil for the hair, most people automatically think of coconut oil because it is easy to find, relatively inexpensive and it seems as if everyone recommends it. But there are other oils out there, many formulated for different circumstances. If your hair is colored, you might look for an oil that is formulated for that specific situation. One can also find oil that has UV protection so your hair is protected from sun damage.
Look through the oils, read the descriptions to find ones that work well for your hair. Decide if you need a heavier oil or a lighter spray oil. I usually end up looking for something that will tame my frizz so my hair looks a bit better instead of looking like it has a mind of its own. I have a couple of spray oils to add a bit of help when my hair needs it and the spray oils are not heavy at all. Let me know what you think, I'd love to hear. Have a great day.