Timebased workflows trigger their workflow actions a specified number of minutes, hours or days, before or after a given date and time.
For example, you could remind a lead owner to chase up a lead that is still in status 'Open' 30 days after the creation day.
To create a Timebased workflow action:
Create a new workflow or edit an existing one. If you need help, this article explains the process.
Your actions will contain a section where you can enable a time based action.
Next, set when you want this action to happen by entering the number of minutes hours or days:
Then, sselect whether this action should happen before or after the date and time field you want to use to trigger the workflow action:
Continue configuring your action as per the processes linked above, depending on the type of action you are setting up.