Your weren’t expecting that. On social media you post a site link to your front page or a particular page on your site and it looks horrible. The image is irrelevant to what you want to say and the text seems random. Why?
Let’s look at Facebook, for example.
The seemingly random image and text that shows up on the Facebook post is because Facebook looks for an image and some meta text to include in your post when you paste a link to the site. If you haven’t specifically set up an image and some meta text for Facebook to grab, it will take what it thinks would be the next best. If you use Yoast as your SEO plugin, you can set this up in the Yoast section of each page. Other SEO plugins will have something similar.
For each page, add some meta text which all social media can grab. You can change it by clicking on the Edit Snippet button in the Yoast section. If you want a specific title, image and text just for Facebook to grab, click on the Social tab (the one under the traffic lights tab on the left of the Yoast section).
You should go through every page and do the same thing – that is, set up the meta text, etc. that you want to show on social media. You should also go through and set up your keywords for SEO purposes while you are there.