set mm= %Date:~3,2%
set dd = %Date:~0,2%
set yy = %Date:~8,2%

ren
C:\Name.txt C:\Name_%mm%dd%yy%.txt

:: Set the date to the format you desire once and store it as a variable
Set TDate=%date:~10,4%%date:~4,2%%date:~7,2%

::Start a Loop which goes to a subroutine through a ‘call’ function (This allow you to assign variables..
FOR %%V IN (%1) DO Call :DoLoop

::Start your complex processing inside this lable so that you can do as many lines as you line inside your loop
:DoLoop

:: Set Single-sided variable to double-sided variable
set OFullFileName=%%V