To get a web address to convert to a clickable link, the best way is to start each with either http://, https://, ftp:// or www.

http://google.com
https://google.com
ftp://google.com
www.google.com

This is more of a suggestion than a rule, the more something looks like a link, the more likely it will be converted.

Alone,
google.com
will not convert, yet adding a forward slash will change this:
google.com/page
This will work for any address with the above prefixes left out.

Another way to create a link is to use a semi colon : with text on either side.
file:google.com
Make sure to add a space after a colon if it is not a link.

Sometimes a valid link will not be converted. If you wish to display a valid link without it being converted, add << to the end:
www.google.com

Some links are not allowed on this site, such as .onion sites:
www.example.onion

Each paste may have a maximum of 180,000 characters.