Problem when adding to theme

Hi, I loved this plugin, but I am having an issue. i added the code to be loaded in funtions.php to the theme but when charging the page you can see the form in the top of the page for 1 second. That is not esteticaly nice and do not know how to correct.

I would appreciate a bit of help.

Site: http://www.chilevapo.cl

https://ww.wp.xz.cn/plugins/formcraft-form-builder/