...
To add in a new argument, ie. the URL link, into an alert/reminder follow these steps:
1.Reminders > Setup
...
2. At Event Filter drop down list select the reminder you wish to update, ie. On Accident/Incident Action Created
...
3. If multiple alerts exist for this event, click on the one you wish to update, ie. Accident/Incident Action Assigned - Assignee
...
4. In the message box you can write in your details, ie. Access to record:
...
5. And then from the Arguments drop down box select your required argument, ie. Link to Record URL
this places the argument into your message.
...
6. Click Save