There is nothing to escape in your code.
Let’s say given function should return only plain text and no HTML entities should be allowed. For example you want to display the search query string.
In such case you should use esc_html.
This way, if user puts <b>ala</b> as search string, your site will print exactly that.
If you won’t escape that string before printing it, it will be treated as HTML code and you’ll see bold word ala only.
But… You have to escape with proper function depending on context.
So:
<h1>You’re looking for: <?php echo esc_html( get_query_var( 's' ) ); ?></h1>
But:
<input name="s" value="<?php echo esc_arg( get_query_var( 's' ) ); ?>"/>
So, let’s get back to your code…
get_the_password_form()
should display HTML tags and they should be processed as HTML code by browser – so you can’t escape it. If you will, you’ll see a string containing HTML tags instead of form.