I have a friend who’s been to yoga a few times, but has very flat flat feet and says her arches are hurting. She was asking if she should wear some sort of supportive shoe, etc to help this out. I had no idea, but thought maybe in your experience you would maybe have some insight?
The good news is that over time yoga will help lift fallen arches, which is why she’s got sore feet right now. Yoga requires us to recruit and use muscles in the feet that may have been dormant or imbalanced for years and can correct many problems over time. It is important that she do stretches and massages for her feet when possible, especially after practice. One I like is sitting on knees with hips on heels and toes flexed to stretch soles of feet for five to ten breaths. Then come back to hands and knees and tap the tops of the feet gently on the mat. She can also sit cross legged and literally massage her own feet for a few minutes. And check out these resources to send to her:
If the problem persists suggest she she a doctor or physical therapist. If arch support is needed, while I am not familiar with this product, I did a quick search and check out what came up:
Hope this helps!