Hi,

What is the best practice for allowing a person to link an external resource, say a URL to a particular task?

For example, in my use case, I have a task that involves the preparation of a document. This document lies in another location, which is collaborated spreadsheet. I am using Custom Fields to implement this. But links appear as text. It would be convenient if links would be clickable.

Are there any suggestion for a better user experience ?

You could use a LongText custom fields and use formatting to present the link. That would be cumbersome, but work.