There is no advice we can give without knowing what kind of tree you have. Different trees have very different requirements. Bonsai is not a kind of tree, it is the art of maintaining any tree in a miniaturized form.
If you don't know what kind of tree you have, post a couple of pictures, showing the tree over all and closer up of the leaves. Probably someone here will be able to identify it for you. It also helps to tell us where you are located. There are hardly any garden questions (even indoor ones) that can be discussed without regard to location/ climate.
Welcome to the forum! If you follow up, we can probably help you.