Vape Coils are essentially what creates the cloud of smoke when you are Vaping. The vaping coils are made from vaping coil wire which is usually made with titanium or stainless steel or sometimes nickel, with the coil you will also require a wick to give the E-liquid to your vape coil. This works by it being a wrapped wire in the wick that will soak up the chosen E-liquid within your tank which is then heated up through inhaling, this is also vaporised when inhaling.
Coils are replaceable, and the recommendable change time varies depending on the type of mod you are using and how often you use it. The average user should change there vape roughly every 2-3 weeks, you can monitor this by how your liquid tastes when vaping, if the coil is starting to burn out you will taste a harsh burn within your experience of vaping and that is an indication of you needing to change your vape pen coil/vape coil wire.
If you are taking consistent drags of your vape you will start to feel and taste your coil burning up on the wick, we would advise you to let it cool off for a minute if you ever experience that or purchase a new coil if the burning sensation keeps happening when smoking on your vape. The vape pen coil is a replaceable part of your vape which can be tailored to a specific vape.