@Said Tifaoui

Dear Dr Tifaoui thank you i will learn that package But my main question is that i want to define distribution from it PDF & CDF functions and test my data to know best fiiting how .

Have a look at ?ks.test

It states that you can specify y as "either a numeric vector of data values, or a character string naming a cumulative distribution function or an actual cumulative distribution function such as pnorm." It also works with custom pdfs eg

# define simple symmetric triangular distribution on [0,1]

ptri

@eik Vettorazzi

Thanks dear professor that was so helpful.

Use adequacy model, define your distribution by coding then run the analysis.

Thank you Mr Falgore