To quickly create graphs and charts, I use a tool called Mermaid on website: https://mermaid.live/

It can be directly used in markdown files like:

  graph TD;
      A-->B;
      A-->C;
      B-->D;
      C-->D;
pie title Pets adopted by volunteers
  "Dogs" : 386
  "Cats" : 85
  "Rats" : 35

Sources:

That's it for this post, thanks for reading!