How to Redirect a URL to Another URL Via WordPress.
Redirect is a way for your website to send a quick message to your reader’s browser and tell them that the page they want to visit has been moved, so their browser can automatically point them to the new page of your choice.
Step 1 – To set the redirection in wordpress, initially install the plugin called as Redirection 
Step 2 – Once installed and activated, choose Tools >> Redirection to setup your redirects. In source URL >> enter the URL which you to redirect and In Target URL >> set the destination URL .
Step 3 – For example, once you have set the redirection from http://mydomainname.in/wp1/about/ to https://twitter.com/. then you can enter the URL or click path it will automatically redirect to destination point.
How to Redirect a URL to Another URL via .htaccess in two steps.
Step 1 – Create a .htaccess file in your cPanel under the directory which you want to redirect.
Step 2 – Once created, You can add the code below preferably at the end of your .htaccess file and save changes.
Redirect /mark/index.html http://gmail.com/
Step 3 – once done, when you the index.html it will redirect to your gmail.com account, based on your need you can set the redirection.