Wordpress : display field from options table in back office settings tab

Question

I manually created a field (named 'test_period') in option table.

I want to display a label and the value in the general tab of settings of back office.

Can you please help me with this request.

It would be great if the field could be editable in back office (editable and saveable in option table)

Answer 1

I googled this great answer: https://www.wphats.com/add-text-field-general-settings-wordpress/

add_filter('admin_init', 'my_general_settings_register_fields'); 
function my_general_settings_register_fields() { 
    register_setting('general', 'duree_avant_expiration', 'esc_attr'); 
    add_settings_field('duree_avant_expiration', '<label for="duree_avant_expiration">'.__('Durée avant expiration' , 'duree_avant_expiration' ).'</label>' , 'my_general_duree_avant_expiration', 'general');
} 
function my_general_duree_avant_expiration() { 
    $duree_avant_expiration = get_option( 'duree_avant_expiration', '' ); 
    echo '<input id="duree_avant_expiration" style="width: 35%;" type="text" name="duree_avant_expiration" value="' . $duree_avant_expiration . '" />';
}