How to view and download receipts for your Facebook ad charges?
First, make sure you're an admin of the ad account. Next, go to Adverts Manager and then Billing. Here is a link to make it easy > https://www.facebook.com/ads/manage/billing.php
There's a date dropdown menu (located above your transactions), you may choose the date range you want for your invoices.
1) Click Download All Invoices.
2) You may selected Invoice Summary as a PDF or CSV file.
3) Click Download.
4) Your invoices or summary will be downloaded in the file type you chose.