Subscribing a user will allow them to keep up to date with any changes made to a particular item. Whenever a change is made, the subscribed user will get an email alerting them to the change. The process will be the same whether you are creating or editing.
When creating or editing an Item you have the option to Notify
certain users by selecting the box in the lower left corner.
Select Save and Close
. The next window Comment and Notify
will allow you to select users to subscribe to that particular item.
When you have finished, select Commit
and emails will be sent to everyone who has been subscribed.
Note: The selected user is required to have read permissions to be subscribed to the item.
For a closer look at subscriptions, check out this article