Firstly install URL Rewrite from here.
Then open web.config of website you want redirect and add the following rule between the rules tag
<rule name=”HTTP to HTTPS redirect” enabled=”true” stopProcessing=”true”>
<match url=”(.*)” />
<conditions>
<add input=”{HTTPS}” pattern=”off” ignoreCase=”true” />
</conditions>
<action type=”Redirect” redirectType=”Found” url=”https://{HTTP_HOST}/{R:1}” />
</rule>