To take advantage of the PayPal Express Checkout payment method:
- enable the system from your Backoffice, under Settings > Payments;
- go to https://developer.paypal.com;
- go to Dashboard > My Apps & Credentials and create an application under REST API apps;
- once you have created the app, copy its Client ID and Secret, present in the Sandbox tab (for test environment) or Live tab (for production environment), to the corresponding fields required in your Backoffice portal;
- select the type of Client ID and Secret Code previously copied in the Backoffice settings: respectively, Test environment for Sandbox and Production environment for Live;
- save the Backoffice settings by clicking the Save button.
Then, for the payment method to work properly, you'll need to:
- log in to your PayPal Business (or Premier) account;
- go to Profile Settings > Sales Tools > Preferences for the website (https://www.paypal.com/businessmanage/preferences/website);
- select "Enabled (required field)" under Contact phone number;
- save the settings by clicking the "Save" button.