You can open an online company by creating a website that explains all that your company intends to do. You should then get a domain name and an affordable web hosting company. You also need to have social media profiles and mailing lists. You can go to http://www.ehow.com/how_2103823_start-online-business.html for more details.
Yes there are some websites that you pay for them to make you a website and you can set the features you want on it with pictures and layout to start a business. I cant remember the name of the site but you could try to Google something like that!