The google keywords are Wordpress and Jhoomla. Look for wordpress website building developers on freelancer or upwork, like sugblund said above.
First, you have to buy a domain name, of your choice. There are many companies, such as GoDaddy, zNetLive etc.
Then, you have to buy a web hosting plan. For this your web developer should be consulted. Since he should look for a plan that supports the language or platform. For example, if he is going to use Wordpress, then a plan that supports wordpress. Version also matters.
Both of these will incur annual charges for renewal.