People love quick fixes. When they have a problem, they want it to be solved rather sooner than later.
That means your lead magnet should be instantly accessible. If your audience has to fill in long forms in order to get the resource, they will most likely quit before even making a single form entry.
You shouldn’t ask people for more than their first name and their email address in exchange for the freebie. The less information they have to provide, the better. That’s why many creators only ask for people’s email addresses.
Once your prospects have filled in the required contact information, they should get easy access to the free resource. Either, they receive it by email or they get clear and straightforward instructions how to access it on your website.