Add a line to the footer

you can insert before or after normal footer widget area !

use these hooks in child-theme functions.php

add_action( 'avia_before_footer_columns', 'enfold_over_footer_widget_area' );
function enfold_over_footer_widget_area() {
  dynamic_sidebar( 'before-footer' );
}

add_action( 'avia_after_footer_columns', 'enfold_under_footer_widget_area' );
function enfold_under_footer_widget_area() {
  dynamic_sidebar( 'after-footer' );
}

then goto widget area and create new widget areas called: either before-footer or after-footer
you can then pull in these new widget areas some shortcodes like:

[av_one_half first]
[av_heading heading='Left Heading' tag='h3' style='blockquote modern-quote' ][/av_heading]
[av_textblock ] Left 1/2 Content [/av_textblock]
[/av_one_half]

[av_one_half ]
[av_heading heading='Right Heading' tag='h3' style='blockquote modern-quote' ][/av_heading]
[av_textblock ] Right 1/2 Content [/av_textblock]
[/av_one_half]

see results here on my test page: https://webers-testseite.de/
little tip: restrict widget
you can set on widget area where to show ( or if it is less work where not to show the widget