link to "external" form

I am migrating a traditional html/css website to WordPress CMS. I have a few forms that are already coded and running properly with their associated php scripts, and I want to link to those forms from the WP site
(I have tried some of the form plugins, and would prefer to just use the forms I have so I don’t have to futz around with the formatting and stuff in the plugins).

My questions:
(1) Is it possible to do this in WP?
(1) If it is: I have a child theme built on a parent. Where should I put the “forms” folder so that I can write the proper relative path? I tried putting it in both the child theme and parent theme directories, but when I click the link, I get “apologies, but no results were found for the requested archive”.
(2) Would it be better to just have the “forms” folder on the server in the root directory rather than trying to put it in with the WP stuff? Would this mean that the WP folders could not then be in my root directory?

Site is currently in development on a local server, so can’t post a link.

Thanks.