Thank you for your reply. The link you sent did not help me.

I already have an email campaign started (Automated Campaigns - "Wish customers a happy birthday" and "Ask your customers' birthday"). I would like for people on Facebook and my website to be able to click on a link for them to add their birthday. How do I proceed?

Thank you 

Ah, that isn't an available feature at this time as customer profiles within your Customer Directory can only be created directly within the Point of Sale app. A possible solution for you would be to use one of our form builder integrations. You can customize the form to ask for the information you are looking for and once complete, you should be able to publish the form and post the link to your Facebook. Once you've collected the customer information, you can create customer profiles for each. To avoid having to create the customer one by one, you can bulk import using our customer template.

Hope that helps get you in the right direction!