I am new in worpdress but I would like to share my code gits in my blog wordpress.

so then I made a gits in github:

(this code it is just a example for this question)

but when I try to share my gits in wordpress I got this:

does anyone know how I can fix that and share my code in wordpress?

note:** my blog wordpress is in a hosting web i dont use the platform from wordpress I have installed the wordpress in my blog. **