How to make subscription form on Facebook?

Heard today like on Facebook pages recently the ability to add a subscription form, that is the type of html form with fields, fill in which admin gets them apparently somewhere on the server.

What is it? Do something new appeared or it was about a regular application for facebook like static html?

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I noticed that when creating ads on facebook is a form of advertising as a "Generation". After clicking on such advertising is precisely similar form with fields for data entry. Long ago there was such a Generation??
July 8th 19 at 11:19

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