Communication with a distant server is done using the AJAX plugin.
construct.net/en/make-games/manuals/construct-3/plugin-reference/ajax
You can find other examples of usage of AJAX in the How do I FAQ for C2.
There is no simple way, as distant server possibly means server coding and maintenance.
I'm not familiar with wix.com and how to setup your communication with their server.
Hopefully someone else already did, or you can find the URL to communicate with in their documentation/support.