To start, you should think about how often you’re going to post, your audience, and your goals.
In general, if you plan on posting a lot of content then it might be worth it to invest in advertising or buying followers. If your goal is building an audience then LinkedIn is a great place to post long-form content and share updates with other professionals in the industry. If your goal is lead generation then Facebook might be the best place for you because they have a huge user base who are actively looking for new information. When deciding where to post make sure that it aligns with your goals.
The Twitter network is great for getting your message out quickly and making announcements in real-time, but it might be difficult for someone to find your content without you constantly tweeting about the same topic.