here is a screen shot of the options page...

Such a feature has never been there on the Options/Preferences page.

If you had it before then it might have been added by a form-fill extension that isn't compatible with Firefox 57+ (i.e. is a Legacy extension).

You can search the Addons website for a 57+ compatible WebExtension.

Would you please take a look at this article (especially the section 'Feature Availability') :

https://wiki.mozilla.org/Firefox/Features/Form_Autofill

Also see : https://www.ghacks.net/2017/05/24/firefoxs-new-form-autofill-is-awesome/

To Happy112 - Before 57.0 I did have the Form Autofill option, but as you can see from my screenshot provided that option is no longer available.

To Cor-el - it was never an addon - see Happy112's link on FF features.

So, I'll take this as a glitch in the 57.0 beta that I hope will be corrected with the next update.

You know : I don't remember this option being In Privacy & Security either, but it must have been there - see this article :

Automatically fill in your address on forms

You could (for now) toggle those prefs in 'about:config' , as mentioned under 'For Testing' here :

https://wiki.mozilla.org/Firefox/Features/Form_Autofill

Thank you for the suggestion - took me a minute to figure out how to do this, I didn't know I had to type the about:config in the address bar...

A note though - it says to toggle the features, however for the first suggestion I actually had to modify it to be "on", the second line was able to be toggled to true.

Thanks again for your time and suggestions.

Here is a screen shot of before the modifications.

And after - I now have the address autofill option - Yeah!

I should have explained about the 'about:config' and not have used the word 'toggle' - just assumed you knew about this 'stuff' (sorry  !)

But : you got the option back - well done, you  !

Thank you for that screenshot - sure put a great big smile on my face  !