Please refer my previous article to learn more
about SharePoint Designer 2013 Workflows.
In this blog you will see how to use “Extract Substring from Start of String" action in SharePoint Designer 2013.
Description:
Here, I will copy a specified number of characters beginning at the start of a string and store the output in a variable.
In this example, I have copied 5 characters from start of “Name” field and stored it in a “ExtractSubstring” string variable and updated the current item “Notes” field to display the output string.
Workflow Design:
Result: