It is the same as spelling.

Orthography refers to the conventional spelling system of a language, such as English or French. It involves the correct way to write words and the rules governing their formation.

Nathan B Derrow has written:

'A catechetical orthography' -- subject(s): English language, Orthography and spelling

I mentioned to my husband (a native speaker of English) that I was going to write about homographs in my next blog post and his comment.

Ves Thomas has written:

'Learning to spell' -- subject(s): English language, Orthography and spelling

'The Canadian spelling program II, 3' -- subject(s): Problems, exercises, English language, Orthography and spelling, Spellers