I don’t know where they order their PCBs, but I think it is place where you order big quantities.
For small quantities, I used these:
I don’t know about your experience making circuits, but I advise you to start with breadboards and protoboards.
Design for elderly and blind people is very challenging, especially because every person has different issues. It is a hot research topic for years. I worked on this topic, you were not even born (I feel so old realizing this). In any case, I can give you advices if you wish.