Social media is a great form of advertising and much of it is free to do so businesses should take advantage of it. It can be hard to know how to use the social media sites as a business but there is a lot of useful information and guidelines out there to help you.
Firstly you need to ensure that you have a complete profile set up on all the social media sites you wish to use. Make sure that you have all the correct contact details set up, the profile is complete in terms of information and images and that you have notifications set up to tell you if someone has commented or contacted you to allow you to reply in a timely manner.
Have a look at your own website and ensure that you have the share buttons on the relevant pages. If you have a news section or a blog, then you should make it very easy for people to like and share your content. Usually there is a number of buttons on each post which when clicked will automatically post a link to your content on that persons social media account. It is surprising at how quickly this can get information shared around.