First of all upload your whmcs file into your client area or subdomain where you want to install whmcs you can download whmcs files here.
After uploading latest whmcs file to your client area extract whmcs zip file in the client area and move all the files to main installation directory of whmcs.
Now open another tab and type your client area url for example yourdomain.com/client area or yoursubdomain.com in depends on your installation directory now your whmcs will start its installation and you will be redirected to whmcs installation setup.
Now go back to your cpanel and create a database and user name for whmcs and connect them both after this copy your database username and database name and paste in your whmcs installation setup you will need a password as will of database so when you are creating database user name keep your password somewhere safe for later use.
Now its time to replace license.php file in your clientarea you have to replace that license.php file with ours . Download your license.php file from here https://mega.nz/folder/uCZUHQiC#CnTLhAw7o2BFTFLaFN9r4w Then upload that file in public_html/vendor/whmcs/whmcs-foundation/lib
Then extract License.zip with replacement.
You can monitor your license status , view additional info and manage your license using our client area please do not hesitate to contact us if you had any issue or need additional support. support is free without extra charge.