By Letter writing, Plurals

I clicked?? on this forums' what I think is hyperlink that said "learn English Letter Writing Grammar and Pronunciation" and saw this thing pop up and upon reading it, it got me thinking how best to align that or if it is aligned in the best way possible. pop-up: Learn and explore the English...

Are they completely the same between writing letters and letter writing? Do we normally write a heading in plural or singular e.g. Writing Letters or Writing a Letter? I think i post this in a wrong section. Anyway, hope any response from you. Regards,