Enable leads access manager on your Facebook account
Go to Meta Business Suite.
If you don't have access to Meta Business Suite, go to Business Settings and select your business, then skip to step 5.
Click the dropdown in the top-left corner and choose your business account.
Click Settings in the bottom-left corner.
Click More Business Settings.
Click Integrations in the left menu, then click Leads Access.
Click Customize Access in the box that appears, then click Confirm. Your Leads Access Manager is now enabled.
Go to your Facebook Leads Center using this url https://business.facebook.com/latest/leads_center
You will see something like this:
Then when you agree Facebook will begin to populate your Leads Center:
Here is how it looks when your Leads Center is populated:
You can download your leads to a csv file by selecting all the leads then clicking on the down arrow on the upper right side of the screen.