Please note that only admins with full control of the Page can download leads.
Go to Meta Business Suite.
Click All tools from the menu.
Click Instant forms.
Click Download next to the form with the leads you want to export.
Choose how you want to download your leads:
Click Download new leads if you only want to export the leads that you’ve received since the last time you downloaded.
Click Download by date range if you want to download all the leads you’ve received during a certain time period. After you select this option, choose the preferred date range and click Download.
A Download leads pop-up window will appear with your form information. Click CSV or XLS to download the leads data in your preferred file type.
Note: You have 90 days from the time a lead submits their form to download their information. Leads expire after 90 days. We recommend that you export your leads data regularly.
If you need further information, please refer to the article link below from Meta.