How to solve canonicalization issue or what is htacess file?

[KateSteel]

How to solve canonicalization issue or what is htacess file?

[SerenMckay]

.htacess file is used to solve the canonicalization issue of a website. It may happen that the home page of the site may take several urls like

1. www[dot]abc[dot]com (with www)
2. www[dot]abc[dot]com/index.html (Index page)
3. abc.com (without www)

The search engines might treat these URL as different and may divide the link juice gained by having various backlinks made with any of these 3 URLs. The link juice gets divided between these three URLs equally. .htacess file is created to have a single URL of the home page so that the link juice is passed onto single URL.

[CarolineMurphy]

First of all, you need to know about your site have which types of server. Mostly these types of server use a htaccess file:
1- Linux, 2- Apache
​​​​​​​
If your hosting account uses one of these types of the server then you can copy below code into your htaccess file.

Options +FollowSymLinks
RewriteEngine on
RewriteCond %{HTTP_HOST} ^ example[dot]com [NC]
RewriteRule ^(.*)$ www[dot]example[dot]com/$1 [L,R=301]
RewriteCond %{REQUEST_URI} ^(.*)//(.*)$
RewriteRule . www[dot]example[dot]com%1%2[R=301,L]
RewriteCond %{THE_REQUEST} ^[A-Z]{3,9}\ /(([^/]+/)*)index\.html\ HTTP/
RewriteRule index\.html$ www[dot]example[dot]com%1 [R=301,L]\

Note: In red highlights, you need to replace example.com with your domain name and in green highlights, you need to replace with your .html or .php index page. Keep in mind do not write just index, write extension too.

After the copy, this code with your htaccess old code, Save it and upload to your root folder where your site has the index page. Hope it will solve.