This quote was part of a comment by Jennifer Egan, author of A Visit From the Goon Squad, about her writing process.
Egan is a novelist and short story writer, and she gave this quote during an interview. In its entirety, the quote reads:
Especially when I’m writing a first draft, I feel as if I’ve been transported out of myself. That’s always a state I’m trying to achieve, even as a journalist — although when I’m working on nonfiction I’m almost never actually writing. I do months of research and then write the piece in a few days.
The part you reference in your question is, of course, the last half of the quote. She is referring to writing non-fiction, something which requires her to do all kinds of research before she ever sits down to write. That is her point, then: when she writes non-fiction, she spends very little actual time writing, as most of her time is spent on the research and information-gathering process.