Docs
Initialise Settings.
Store all settings in a single database entry and make sure the $settings array is either the default or the settings stored in the database.
includes/abstracts/class-evf-settings-api.php
Return the name of the option in the WP DB.
Get the form fields after they are initialized.
Processes and saves options.
Get option from DB.
includes/abstracts/class-evf-integration.php
Init settings for gateways.
Update a single option.