If the plugin that you’re trying to do this with does not use standard posts and other WP editors then there is no easy way to add fields.
the_field() displays the value of the field and not a field for entering something into.
You might be able to use acf_form() here…… maybe….. https://www.advancedcustomfields.com/resources/acf_form/ and if you supply the correct post ID and set 'form' => false
it should work.