⟩ Explain me can we run a free contest on our Facebook Page where fans like and share our regular posts to win?
Knowing the rules and guidelines for each platform is absolutely necessary. Mainly to implement best practices, but also to avoid violating the terms of service, getting suspended or kicked off. The short answer to this question is “no”. Facebook fights against clickbait posts that encourage liking and sharing, but you can still run a proper contest and give additional points to those who engage on social media.