In order for your website to be seen on the internet you must have a hosting company provide you space for your website. These companies provide all the basic services for your new website. All your landing pages and sales pages are hosted on your own website and domain. All your marketing activities are based on these websites.
The companies listed below are reliable and have a long history.
BlueHost is well know as a hosting platform. Good support and service.
GoDaddy has been my domain company for over 17 years. Good service and very reliable. They now doing hosting as well and i have heard good things about this service.
Hostgator is a popular option as it is easy to use and work with. I had one website hosted their before I shut it down about 2 years later. I had no issues but i have heard service has dropped over the last couple years. Fast growth can do this to a firm. I expect they will realize this and fix the issues.