Filter to change ‘Add Attribute’ label

You can use this filter in your theme and can modify the default Add Attribute button label for adding attributes while uploading media from media tab.

Add the following code in your theme’s functions.php file:

    function change_rtmedia_upload_add_attribute_label( $label ){
    $label = "New Add Attribute Label";
    return $label;
    }
    add_filter( "rtmedia_upload_add_attribute_label", 'change_rtmedia_upload_add_attribute_label', 10, 1 );

Where “New Add Attribute Label” will be name which you want to use.