Create a simple printable document with Objective-C Mac OSX

Create a simple printable document with Objective-C Mac OSX

I've reached the last stage of development on my very first Mac OSX app
(and first program ever). Basically, the program takes user input for
various students, calculates grades for three components of a seminar, and
then calculates the final certificate type the student is eligible to
receive. What I need to do now, is press a button, and generate a "To whom
it may concern" letter about the student and a certificate that uses the
three component grades.
Each student will have two documents: a letter, and a certificate.
My questions is this: What is the best way to go about doing this? My
first attempt was to create a rtf document. However, I couldn't find good
resources to assist me. My second thought was to create a pdf, but again
all I found was iOS resources. I also thought it would be possible to just
create a new window with a view with the documents appended one after
another or to use HTML but I'm not sure how that would work.
What is the best approach and do you know of any resources (tutorials,
guides, books) that will help me? I guess I'm stuck at an intersection and
I'm not sure which path to take. I'd have to learn any of the methods from
the ground up, but I'm not sure which option to pursue.
Thanks!