If you need to redirect your domain name with "WWW" you can use the following htaccess code for Apache based web servers.

Redirect with WWW htaccess

Options +FollowSymLinks
RewriteEngine On

# Mention Domain name

RewriteCond %{HTTP_HOST} ^example.com [NC]
Rewriterule ^(.*)$ http://www.example.com/$1 [R=301,NC]

# OR
# get domain name automatically.

RewriteCond %{HTTP_HOST} !^www\.(.*)$ [NC]
RewriteRule ^(.*)$ https://www.%{HTTP_HOST}/$1 [R=301,L]