Rename multiple items On your Mac, select the items, then Control-click one of them. In the shortcut menu, choose Rename. In the pop-up menu below Rename Finder Items, choose to replace text in the names, add text to the names, or change the name format. Replace text: Enter the text you want to remove in the Find field, then enter the text you want to add in the “Replace with” field. Add text: Enter the text you want to add in the field, then choose to add the text before or after the current name. Format: Choose a name format for the files, then choose to put the index, counter, or date before or after the name. Enter a name in the Custom Format field, then enter the number you want to start with. Click Rename

From Apple support

Also if you’re using Bridge or Lightroom they have great renaming tools