Documentation of self-created function

after having created an awesome :) function in Matlab, I want to add a documentation to this function, such that when the user enters

doc myfunction

he gets a documentation window of my instructions on how to use this function.

I am not completely sure, whether this feature is available to functions shared on the mathworks file exchange only. Should this be the case, how can I then add a help text such that the user gets my instruction on how to use the function when he enters

help myfunction

?

I tried this. However, my code (below) does not work. When I enter

help my_boxplot

the command window prints 3 empty lines...

function y = my_boxplot(x);
% MY_BOXPLOT Plot a boxplot of a datatable with 2 columns.  
%       The first column will be assigned to the x-axis, while the second
%       column will be assigned to the y axis. 
%       REMARK: The dots displayed in the respective boxes are the means of
%       the corresponding range (whiskers).
%       the MEDIAN 

Thank you for your time so far.