As previously, it can use the econometric software such asa Eviews or Oxmetric. What is important is the concept of ARCH & GARCH not just related software.
I highly recommend you to study the following textbook.
Brooks, C., 2002, Introductory Econometrics for Finance, 2nd edition, Cambridge University Press.
It is very easy to follow. Sample instructions and output from the popular computer package EViews will enable you to implement volatility models themselves and understand how to interpret results.