How to appeal to Amerihealth Delaware for non-preferred drug authorization?

idk how to tag this i’m not reddit savvy so forgive me.

I have ADHD, Vyvanse was reccommended to me after tryin focalin as a child and recently atomoxetine, which has been ‘okay’ but the capsules are difficult to swallow because of the texture and i don’t really feel or see much difference in my behavior/focus. My doctor wants to prescribe me the chewable vyvanse tablets(idr what mg), but my insurance continues to deny or halt the process. What can I do in terms of appeals/contacting them to get them to give authorization for the non-preferred medication? I can’t stand the capsules anymore and I need something I can take as-needed, like Vyvanse. I want to at least try it. I’m not very prone to addiction or anything despite the ADHD, I don’t drink really ever, don’t do any recreational drugs, nothing. I don’t do anything that’s addictive except use the internet. I want to be able to focus properly on days I work(self employed from home) but not have to worry about forcing that with meds on days I’m off as well.

Also, what do I say to them when I contact? Do I call or fill out forms, can I do any of this electronically or through email, and is there a way to word things so they are more likely to let me use the medication?

TL;DR

I’m self employed, broke, use medicaid Amerihealth insurance for Delaware state, and I have adhd. I want to use non-preferred medication Vyvanse because i’ve tried 2 meds accepted by insurance before and they both do not work well. What do I do?