Help! Not producing enough milk!

Hello ladies! My friend just had her baby a little over a week ago. She just isn’t producing enough milk and is having to supplement with formula which is frustrating her. Do any of you have solutions to increase milk supply that have worked for you? Thanks!

Update:

Thank you ladies! I sent her the info. She went in to a lactation specialist and they weighed baby had her nurse then weighs babe again. She did not get enough milk. She will be going back on Monday. Hopefully these tips will help her!