Click on Plugins -> Editor, then select Password Protected and click on:
password-protected/theme/password-protected-login.php
Between:
<body class="login login-password-protected login-action-password-protected-login wp-core-ui">
and
<?php do_action( 'password_protected_login_messages' ); ?>
<?php do_action( 'password_protected_before_login_form' ); ?>
put:
<div id="login">
<h1><img src="LOGO_URL" alt="SITE_NAME" width="300" height="auto"></h1>
<br/><p style="text-align:center">YOUR_NOTES</p><br/>
instead of what’s between the above mentioned lines right now.
Done.
Note: This is NOT an update proof solution but it works for the while you work on the site.
