You can get some good mass file renaming utilities as freeware or shareware.
For years now, I have used a mass file renaming facility built in to xplorer² file manager (zabkat.com). It is a major timesaver when renaming multiple files. There is a facility to insert variable names ("tokens") into the file name - e.g., sequenced numbering starting at "n".
The above screenshot is from my desktop, in the process of renaming a group of digital photo files named "SDCnnnnn" to "Antarctica $01.jpg" which gives them a sequential numbering starting at "01". I've clicked the "Preview" button, so that I can see what the filenames will look like before actually committing to those names. This is just one example of what you can do with this mass file renaming facility in xplorer². There's lots more clever stuff in there.