The Facebook Ads Manager can be a little complicated when you get started. When you choose Create an Ad, you’ll see a number of choices.
Initially, I would say focus on Traffic and driving the lowest cost per link click to your website. Engagement has a few different options under it including Page Likes, Post Engagement, and Event Responses. If you are looking to Boost posts or get more Likes, then this is a good choice.
If you have the Facebook Pixel installed and you are ready to track conversions, then you can choose Conversions. Make sure you know the difference between running a Conversion ad vs. Traffic.
The Lead Generation ad is not a bad one to test as well but make sure you know how to get your Leads from your Facebook Page and that you are following up.
Again, you can test your options and see which one gives you the best cost per result.