What are the random characters in every post’s URL/slug?

You might have noticed a unique set of characters being attached to every post’s URL as shown below. That is the post id.

https://blog.example.com/my-example-post-title- 1cko8rasqs5nerasf0g

This is the standard structure for superblog URLs. You need not worry about them.

Do they affect SEO?
No.

Can you change it?
Yes.