Sometimes you may have to leave a link inside a task or a notification such as for me was to leave a app studio app installation link that changes every time i deployed a newer version.
It was not feasible for me to to edit the task or change the notification to change the link. So, i found a content type called "link to a document", which you could add to the document library. After adding the content type, you will be able to add a link inside it that will be different than the main link that you would provide in the task and notifications. Also, while adding links to notifications and tasks always insert a link and do not just paste the link (which in my opinion looks cleaner).
If the link is too long to add for the link to a document, first create a tiny URL by visiting to one of the URL shortening sites, and use that shortened URL as the link to a document, WALLAH!!!