You can stain balsa wood.

Wood stain is abosorbed into the wood, so the wood takes on the color of the stain. This is why the features of the wood are still visible, unlike with paint.

Wood stain is for sealing and emphasising the natural colour of wood

1) varnish

2) use a wood stain

There are thousands of wood stains, and all look different on various woods. It is best when matching to take a sample to the store and compare. When you settle on 1 or 2 , test them on a small piece of the wood you want to stain first.