Programs enabling conversion of the file:
If your objective is to convert the file from M4V to the file MP4, you can use any of the applications listed. M4V to MP4 conversion process in every program intended for this purpose (so-called converters) is very intuitive and everyone is able to manage converting a file.
However, bear in mind that the list may also include programs to support and work with the indicated extensions M4V and MP4 - and not only converters. In such a case, you need to open the source file M4V and from the options available in the program, choose ”Save as... MP4" or "Export to MP4".