Send custom email ->modifies Invalid HTML

I am trying to make custom HTML email
On saving it reformats the HTML code which makes it invalid

My Code:
<h2><a href="https://(domain)/wp-login.php?action=rp&key={{CODE}}&login={{NICKNAME}}" target="_blank">Reset my Password</a></h2>

After Saving
<h2><a href=\"https://sound.codes/wp-login.php?action=rp&key={{CODE}}&login={{NICKNAME}}\">Reset my Password</a></h2>

Is there a way to change this ?can I modify some other file to hardcode the email body html code ?