You can create ads targeting people you know about from other sources; for example, your newsletter subscribers. Such targeting configurations are called Custom Audiences in the Facebook Ads Manager.
To create Custom Audiences, you can upload customer lists in different file formats like MS Excel or import customer lists from third-party services like Mailchimp. Before uploading, the list will be hashed for security. For information about how to hash a customer list programmatically, see Custom Audiences.
In addition to using Facebook targeting technology you can easily plug in other media channels. Your lists may be based on emails, phone numbers, Facebook user IDs, or mobile advertiser IDs.
Information you provide will be matched with people on Facebook to create an audience. Your contacts won't be notified that you've added them to an audience, and we'll never contact them without your permission.
At the step where you define your ad audience, choose Create New > Custom Audiences and pick the option Customer File.
Pick one of the following options to import your customer list:
Upload a data file that contains emails, phone numbers, Facebook user IDs or mobile advertiser IDs. You can upload files in .csv or .txt format. The files can include records on separate lines or in a list separated by commas.
Copy and paste emails, phone numbers, Facebook user IDs or mobile advertiser IDs of your customers. You can copy columns from a spreadsheet with one record per row or a list of records separated by commas.
Import a customer list from the third-party email service MailChimp. Email addresses from your MailChimp list will be matched with people on Facebook to create an audience. Facebook doesn't store your MailChimp username or password.
After importing your list it will take up to 30 minutes for your audience to be ready for use. We'll notify you when your audience is ready. You can also check status in the Ads Manager.
While your custom audience is being processed you can continue creating your ad. At a later time you can use the same custom audience again.