Please refer to my previous article to learn more about SharePoint Designer 2013 Workflows.
In this blog you will see how to use “Set Time Portion of Date/Time Field” action in SharePoint Designer 2013.
Description:
Creates a timestamp, and stores the output value in a variable. You can set the time in hours and minutes and add a current date, specific date, or lookup.
In this example, I have a custom list named “Custom” in which I have attached this workflow. When I run a workflow for an item it sets the time in hours & minutes and stores the output as text in the current item “Notes” field.
Workflow Design:
Result: