Resolving http to https in config files

I’m trying to set up a secure checkout on my site and got this response from GoDaddy:

“It would be something you would have to do with your WordPress files. Check your config files and such to make sure they are referencing https and not http.”

Unfortunately I have no idea what this means or how to do it. Any suggestions?

http://www.promisetofeelem.com

https://wordpress.org/plugins/woocommerce/