I am currently designing a web form for the Online Travel Insurance System and I am thinking of hiding the optional fields since there were so many of them. Like the image below.
I put a
Show More link button that will show all the optional field under the Passport Details section. I also hide the Emergency Contact Information and Accompany section since all the fields under them are optional.
This will discourage the users from inputting a value in the optional fields, but I think it will improve our sales but I do not have any reference to prove that. Is there any UX case-study about this matter?
I have found this study from the UXMovement Site about user making mistakes:
... The lesson is this. When you put more and more fields and elements on your forms, you increase the chances of your users making mistakes. When you’re dealing with money, this can cost you.