"I know how to write."
Translation:Я умею писать.
писа́ть = to write пи́сать = to pee
these are very easy to confuse since only the accent is different, and the spelling is different.
(True Story) An American boy was trying to cheer a Russian girl up who was morning over a break-up. He meant to say "I will WRITE to you from America." He confused these two words and the Russians could stop laughing. I'm not sure if this would be considered a failure or success, but needless to say He was very embarrassed, and for at least a moment she forgot about the break-up.
"уметь" and "знать, как" are both "to know how to" in English, but the latter only means having knowledge. Я знаю, как писать, но никогда не пробовал делать это - I know how to write, but I never tried to do it. Here "to know how" can mean "to be told" or "to have read about". Уметь presupposes that you did that thing, and most probably not once.