wpautop

I have seen in this thread https://wordpress.org/support/topic/plugin-simple-fields-remove-wpautop?replies=9 that there is a filter to remove the <p> tags which wordpress applies automatically but What is the actual code you have to put in function.php to disable it for simple fields? Using the standard wpautop way doesn’t work for simple fields

https://wordpress.org/plugins/simple-fields/