Make sure you're happy with the preview example at the bottom of the Rename panel, then click Rename.Note that if you selected a number format, you can use the Where dropdown to choose whether the sequential numbers appear before or after the common name of your files. Enter a starting number for the file series in the Start numbers at field.Enter a common name for your files in the Custom Format field.
We're going to use Name and Index, but you can optionally select Name and Counter or Name and Date. In the next dropdown, select a Name format.
In early versions of Mac OS, users looking for a way to quickly rename multiple files simultaneously (commonly referred to as batch renaming) had to use the command line or download and install a third-party tool dedicated to the task.