How to add custom fields in wordpress screen settings?

Question

WordPress

Missing custom fields in wordpress
Since I don’t use them often, I didn’t track after what actions they disappeared.
With what it can be connected?
They are no longer on the "Screen Settings" tab in the admin panel:

Answer 1

Maybe you updated the theme, and the creation of custom fields was written in functions.php ?
To avoid this, create a child theme. Well, for custom fields, use the ACF plugin...

Answer 2

It turned out that the fields are hidden by the ACF plugin. Earlier there were also "Custom fields" and ACF. At some point, after the update, ACF hid the custom fields.
The trouble was that one of the pages displayed JS code through the Custom field. It continued to load, although the field was no longer shown.
As a result, I turned off ACF, arbitrary fields appeared, removed js code, turned ACF back on.