Select the Fixed date or Property-based workflow type when creating your new workflow. These options will allow you to center your workflow on a calendar date or contact date property.
In a fixed date or property-based workflow, any delays are relative to the selected fixed date or the date property value set on the contact's record. You will need to decide whether the action will execute before, on or after the specified date and at what time.
If you would like the workflow to recur annually, you can toggle the checkbox to make the workflow Recur annually on that fixed date or contact property date. You can choose this option when choosing which property or date the workflow is centered on.
At this time, there is no way to set up a workflow step to execute on a recurring day of the week.