Form ID

To get your Form ID:

Login to Business Suite.
Select the Page (Your account) containing the Form From the left menu > Dropdown.
Click All tools from the menu.
Click Instant Forms under Advertise.
Select the Form you want to get its ID from the Lead Ads Forms List.
The Form ID should be listed under Form details section.

Lead ID

To get your Lead ID:

This requires to download your leads from your Facebook Page.
Login to Business Suite.
Select the Page (Your account) containing the Form From the left menu > Dropdown.
Click All tools from the menu.
Click Instant Forms under Advertise.
Click Download button of the Form that contain the required lead. Your leads will be downloaded to a CSV file.
The Lead ID's should be listed under id column in the downloaded CSV file.
In order to use Lead ID, make sure to copy it without its prefix, the [ l ] letter & colon character [ : ]. (Example: l:xxxxxxxxxxxxxxx).

Please find below a reference to REST API documentation
https://developers.facebook.com/docs/marketing-api/guides/lead-ads

Updated on: 20/07/2022