Vaping may or may not be allowed indoors depending on your location. Many workplaces, offices and other public buildings have policies which prohibit vaping in areas where smoking is also banned.
If you want to vape indoors, and you are unsure whether it is allowed, it is always best to check first with the owner or manager of the building in question.
However, in locations where you are allowed to vape indoors, it is a good to idea to ask first if those around you object. You should also avoid vaping directly at others or blowing large vapour clouds.