WP-E-Signature (Approve Me) admin permissions.

bh_set_esig_super_admin.php

<?php
/**
 * Sets/overwrites the super-admin user-id in the e-signature cache.
 *
 * Allows editing documents and saving documents as PDF,
 * but not previewing documents in draft or viewing signed documents in the browser.
 */
function bh_set_esig_super_admin() {

	/**
	 * Seems to be done as the plugin files are loaded, so this is just precautionary.
	 *
	 * @see WP_E_Digital_Signature::setup_constants()
	 */
	if ( ! defined( 'ESIG_CACHE_GROUP' ) ) {
		define( 'ESIG_CACHE_GROUP', 'esig' );
	}

	/**
	 * Get the current user so we can check are they an administrator.
	 *
	 * @var WP_User $user The currently logged in user.
	 */
	$user = wp_get_current_user();

	/**
	 * If we're in the admin UI and the user is an administrator.
	 */
	if ( is_admin() && in_array( 'administrator', $user->roles, true ) ) {

		/**
		 * Set/overwrite the cache entry for the e-sig super-admin to the current user's user-id.
		 *
		 * @see WP_E_User::esig_get_super_admin_id()
		 */
		wp_cache_set( 'esig_superadmin_user', $user->ID, ESIG_CACHE_GROUP );
	}
}

add_action( 'init', 'bh_set_esig_super_admin' );

bh_user_swithing_signed_docs_url.php

<?php
/**
 * Uses User Switching plugin to change the My Documents / Signed link to switch into the super admin's profile first.
 *
 * @see WP_E_DocumentsController::index() $template_data['manage_signed_url']
 *
 * @param array $template_data
 *
 * @return array
 */
function bh_user_swithing_signed_docs_url( $template_data ) {

	if ( ! class_exists( 'user_switching' ) ) {
		return $template_data;
	}

	if ( ! class_exists( 'WP_E_Digital_Signature' ) ) {
		return $template_data;
	}

	$current_user = wp_get_current_user();

	if ( is_admin() && in_array( 'administrator', $current_user->roles, true ) ) {

		// Clear the cache so the correct user id is returned.
		wp_cache_set( 'esig_superadmin_user', false, ESIG_CACHE_GROUP );

		/**
		 * E-Sig doc comment suggests this is void but the function returns $_instance.
		 */
		$esig = WP_E_Digital_Signature::instance();

		/**
		 * The e signature user helper class.
		 *
		 * @var WP_E_User
		 */
		$esig_user = $esig->user;

		$super_admin_user_id = $esig_user->esig_get_super_admin_id();

		if ( $super_admin_user_id !== $current_user->id ) {

			$super_admin_user = get_user_by( 'id', $super_admin_user_id );

			$super_admin_login_url = user_switching::maybe_switch_url( $super_admin_user );

			$redirect_to = get_admin_url() . $template_data['manage_signed_url'];

			$super_admin_login_manage_signed_docs_url = add_query_arg( 'redirect_to', $redirect_to, $super_admin_login_url );

			$template_data['manage_signed_url'] = $super_admin_login_manage_signed_docs_url;

		}

		// Set the super-admin to the current user.
		bh_set_esig_super_admin();
	}

	return $template_data;
}

add_filter( 'esig-document-index-data', 'bh_user_swithing_signed_docs_url' );