You can’t. Since your site does not have HTTPS, an error will be shown before .htaccess can take effect (Thanks Admin, learned from my earlier mistake).
Getting an SSL certificate is quite easy, just go to app.infinityfree.net/ssls and pick one. If you really don’t care, just choose “Self-Signed” than add the code below to your .htaccess file (Since the certificate will only be used to redirect to the unsecured version, they type of certificate does not matter).
NOTE: The code below wll only work if you have a valid SSL certificate
RewriteEngine On
RewriteCond %{HTTP:X-Forwarded-Proto} =https
RewriteRule (.*) http://%{HTTP_HOST}%{REQUEST_URI} [L,R=301]
Note: It is recommended that all sites have an SSL certificate. If you do not have a certificate, all your websites data is broadcasted in a way that anyone can intercept it. This means that usernames, passwords, and other sensitive data is not safe!