Major social web services (such as Facebook, Instagram, Twitter, Microsoft and Google) have a page where you can click a button to export your data - posts, account data, login information, meta data, images, etc...
Most other companies (such as Insurance, Banks, etc) only allow exporting your data if you email/phone them with the request, not providing a way to do that through their website.
For social network websites to comply with GDPR, is there anything that says that they must provide a button to export user data, or is it enough to accept requests through emailing and the staff will securely send a PDF with the export?