Sometimes if code is not made available to download it must be transcribed or copied (I prefer the select content, crtl-c (copy), crtl-v (paste), route.  However sometimes the code must be decoded due to the way 2-D math is interpreted when it is copied to Notepad. 

For example,

a:=(x,t)->5*x+3*t*x^2    

in Standard mode looks like       a := proc (x, t) options operator, arrow; 5*x+3*t*x^2 end proc     
however looks fine copied from classic maple  

And the output from an example Matrix   b:=Matrix(2,2,[[1,2],[3,4]]);

looks like b := Matrix(2, 2, {(1, 1) = 1, (1, 2) = 2, (2, 1) = 3, (2, 2) = 4})    from standard mode

and    b := RTABLE(50453028,MATRIX([[1, 2], [3, 4]]),Matrix)    from classic mode

It is not possible to copy content directly from Maple to Mapleprimes, in the crtl-c  crtl-v fashion.    An alternate way is to upload your file and use include contents.

It would be nice to simply crtl-c crtl-v directly into the mapleprimes editor.  I think most people use notepad (as I see a lot of the interpreted code) and because it's the quickest way.  I find copying from Word, which properly interprets Maple's 2d math, a little buggy trying to paste it in the primes editor and more time consuming.