I assume by forgot page you mean forgot password? Your question says all you want to do is add a link to the placeholder but i don't see any placeholder. What you are asking is very basic and a simple google search of anchor tag or links comes up with millions of results
To simply add a link to your page you do something like
<a href="/your/url/to/forgot/password.html" class="link-class">Forgot Password</a>
add link to html[
^]
Given this is a poorly worded question, if this is not what you were seeking, feel free to update your question with a clear explanation of your issue, don't assume we know anything about your project.