It is generally okay to burn your manifestation paper after using it, as long as you are doing so safely and in a way that is not harmful to yourself or others.
Burning the paper can be a symbolic way of releasing your intentions and allowing them to manifest in the universe.
However, it is important to use caution when working with fire and to make sure that you are not putting yourself or others at risk. It is also a good idea to check with your local laws and regulations to make sure that burning paper is allowed in your area.