You can give away all of your property over which you have complete ownership. You cannot give away property which you do not own. In some cases, you may have a life interest in the property, i.e. when someone has given you the property under their will only to use for your lifetime, but you do not own it.
You may include any movable or immovable property which you have acquired by yourself. If you are a member of a Hindu joint family, you can only give away your portion of the ancestral property in a will.