When you have to rename files you usually do it manually, but if you have hundreds of them it`s better to have a program like RName-it. It is a practical free utility that lets you rename en masse as many files as you want, and is very easy to use and needs no installation.
In RName-it you can add prefixes to the selected files, change the extensions, put the added prefixes in capitals to identify them better, insert character chains in the position you indicate in the filename, replace set chains for others, delete them, etc.
RName-it also lets you preview how the results will end up before finishing, so you can confirm and verify that they are what you want.