You can get the current date in one of two ways: from a field in the table, or from a script.
I like using a script because it is cleaner. The script would have only one or two lines of code. You can probably find example code online. If you are interested in learning how to code, you may like my automation helper scripts, which includes a simple timestamp script.
But if you are not comfortable with a script, you can use a formula field with TODAY() or a field that shows the last modified time of a field that was edited to trigger the automation.
I dislike using TODAY() as it is resource intensive and can have timezone issues.
