"mv" command renames the file, It needs only the source of old file and the location will be in with a new name, or with the same name.
It is obvious from the command "mv" that moves files, however It renames them too as well.
An example to demonstrate renaming a file in the same path :
mv {old-file-name} {new-file-name}
mv file myfile
In fact, It moved the file in the same location and gave it a new name.
Note : You can do the same example, but changing the name is necessary or you will get an error.
This example moved a file from a path to another without changing Its name
mv {old-path/file-name} {new-path/file-name}
mv ~/Myfile ~/Desktop/Myfile
This example changes the name and the path as well :
mv {old-path/file-name} {new-path/new-file-name}
mv ~/Myfile ~/Desktop/Mynewfile
Note : The same can be done with folders.