The command for a Histogram in Mathematica is Histogram:

http://reference.wolfram.com/mathematica/ref/Histogram.html

I'm not familiar with what a Frenquency Table is. From what I see online, it's a list of how often each number occurs in a list. You might be interested in these functions:

http://reference.wolfram.com/mathematica/ref/BinCounts.html
http://reference.wolfram.com/mathematica/ref/Tally.html

Normally, you don't fit equations on histograms. That's not the best way to estimate the parameters of a distribution. Mathematica provides a function for this called EstimatedDistribution. If you really do want to find a least squares fit to an empirical PDF, then you may want to use NonlinearModelFit.