Asbestos is a mineral fiber which was added to products to make them stronger, fire resistant and insulating. In the years leading up to 1970 it was used in many different types of building and insulation materials.
If you breathe in high levels of these fibers, it will lead to an increased risk of lung cancer, but the symptoms might not show up until a few decades later.
If you have an older home, there is a risk that asbestos fibers are released when you do a renovation or repair. If you aren’t sure whether or not a certain material contains asbestos, you should treat it as if it does. Unless it is labelled, there is no way to tell from a visual inspection.
If the material is in good condition, there is no need to do anything to it. It should not be a risk. If there is a need to repair or remove it, you should consult a professional, since handling the material is very likely to release fibers.
There are many companies that have staff trained specifically in asbestos removal. They will have the protective equipment needed and the experience to work with, as well as dispose of asbestos.
You should do some research to make sure that it is a reputable business and that you can rely on them doing the job properly and safely.