I thought she regained her eyesight after she reincarnated but still pretend to be blind? That's how she could read and write?
I thought so too!
From spoiler i read, she back before she lose her eyesight. Make an accident that make her fake blind before she sacrifice her eyes for fake daughter. But the manhwa not make this adaptation. Maybe because they have deadline. Usually manhwa has chapter deadline that need fulfill no matter how absurd the story will go. Unless it's really popular and can become money mine for publisher
How the fuck is she able to write letters and read books when she's blind?? The manhwa should've explain "how" instead of readers presuming "ohhh, it's probably because of magic"