On wealthy worlds (like Hosnian Prime), it's practically unheard of, according to the canon novel Bloodline:
Leia settled into her chair, picked up her napkin - and stopped.
Something was written on the paper streamer on plate. Actual writing. Virtually nobody wrote any longer; it had been years since Leia had seen actual words handwritten in ink on anything but historical documents.
Bloodline Chapter 13
It's noted later in the book that paper writing was still common on Ryloth, a traditionally economically-poor planet:
"Is it all written on paper?" Korrie said in despair, about three hours into their work in the Ryloth archives.
"Except the stuff that's written on tanned hides" Leia put the ancient vellum to one side, wrinkling her nose. "Or on wooden tablets or rolls. But yes, it's all either written or printed."
Only Joph Seastriker's thick shock of golden hair showed behind his high stack of leather-bound volumes. "Could they seriously not afford regular holograms or computers or anything? Ever?"
"No, Lieutenant Seastriker, they couldn't." Leia kept her voice civil - but her staffers needed to understand this. "Ryloth has never had much in the way of resources, and whatever they had was traditionally taken away from them by either the Niktos or the Hutts. They learned that if they wanted to preserve their own version of their history, this was the only way they could do it.
Bloodline Chapter 16
Presumably handwriting was similarly more common on other less wealthy planets.