Nice drawings
Lighting is a whole subject in itself. The simplest is to use window light, preferably from a window that faces away from the Sun. A simple reflector can lift the shadow areas.
You can get more control , and see what you are getting by using a simple lighting set up with two lights. You can use anything from desk lamps to proper studio lights with photoflood bulbs.
If you use lights of equal strength, putting them at 45 degrees to the subject on either side of you at head height will result in even lighting with no shadows. Moving one light further away will increase the shadows on this side, and you can also change the angle that you have the lamps and see what the effect is. Proper lights will have 'barn doors' to make changes to the lighting, and can take 'snoots' to focus the light more tightly. You can make these from cardboard and tin cans if you are handy, or know someone who is.
You can also change the height of one or both lights. Bear in mind that a model will feel uncomfortable because of the light being in their eyes and may get hot from the heat from the lamps. Once you are used to them, you won't have to spend much time setting them up, so the model won't be so uncomfortable.
As you are going to use the pictures to make drawings, I suspect you will not be bothered by shadows cast on the background, but they can be reduced/eliminated by moving the subject away from the background, or lighting it seperately with another light.
Don't forget if you use tungsten bulbs to change the white balance setting.