Also (this is not related to wrapping) you place links outside of paragraphs with markdown:

```markdown
Words before a link in a line that should wrap, [words in link], then words after the link.

\[words in link]:https://some.link.but/it/could/be/really/long/sometimes

Another paragraph
```

(Except without the `\`, that's just there to stop github interpreting it as an actual link definition - probably due to a bug in their parser)