To install WHMCS, follow the below steps for manual installtion:
-WHMCS can be downloaded from the official website.
-Files should be uploaded to your server.
-Make a database and a user.
-In your browser, run the installation script.
-During installation, enter your license key.
-Complete the setup by giving all required information.
-After installation, remove the installation directory.
-Configure settings in the WHMCS admin section.
==> You can also install WHMCS through cPanel-> softaculous where you an directly find option to select and install WHMCS, make sure you have a valid license to it through https://dollar2host.com/whmcs-pricing.html