Between these triple-dashed lines, you can set predefined variables (see below for a reference) or even create custom ones of your own. These variables will then be available for you to access using Liquid tags both further down in the file and also in any layouts or includes that the page or post in question relies on.

---
 layout: post
 title: "Post Title Ghoes Here"
 post_id: 1
 date: 2021-01-02 8:14:30 +0600
 tags: education
 categories: [Trending]
 post_image: /assets/image/blog-img-1.jpg
 author: themeix
 featured: false
 excerpt: Here is the example text for the post excerpt
 comments: true
 author_id: 3
---