Answers for "htaccess file to redirect to index.html"

redirect to http to https .htaccess

<IfModule mod_rewrite.c>
    RewriteEngine On
    RewriteCond %{HTTPS} off
    RewriteRule (.*) https://%{HTTP_HOST}%{REQUEST_URI} [R,L]
</IfModule>

https redirect htaccess

RewriteEngine On 
RewriteCond %{HTTPS} !on 
RewriteCond %{REQUEST_URI} !^/[0-9]+\..+\.cpaneldcv$ 
RewriteCond %{REQUEST_URI} !^/\.well-known/pki-validation/[A-F0-9]{32}\.txt(?:\ Comodo\ DCV)?$ 
RewriteRule (.*) https://%{HTTP_HOST}%{REQUEST_URI} [L,R=301]