It is unclear to me whether you're an end user who needs to fill out forms or an IT person who needs to build a software solution that allows end users to fill out forms.
If you are an IT person then use a web app and let both the mobile and desktop apps use a single app to do the same thing. That would be my recommendation. The data would need to be stored in a shared database somewhere.
If you're an end user then consider creating a fillable PDF and emailing it to the person or use a document service like DocuSign that allows you to create a fillable form and then send out an email to have someone fill it out.