Yes, definitely. The first step to it is to stop giving them milk formula and latch, latch, latch!
It's a demand and supply thing. See, if you give your kids formula, you're telling your body to produce less milk because it's not needed, anyway. So best thing to do is first, unlilatch, complement it with healthy nutritious foods especially galactagogues like malunggay, leafy greens, seafoods, oatmeal, etc. Lastly, never doubt your supply! Always think it'll be enough and think positive thoughts always. Remember, stress lessens milk supply.
Hope this helps. Happy breastfeeding!