Надо перед расположение писать .\\ (.\)
Исправный код:
import document
f = ".\\document\\Литература.docx"
@dp.callback_query_handler(lambda c: c.data)
async def send_file(query: types.callback_query):
with open(".\\document\\Литература.docx", 'rb') as f:
if query.data == 'button1':
await query.message.answer_document(f)
with open(".\\document\\Литература.docx",
"rb") as f:
if query.data == 'button2':
await query.message.answer_document(f)
with open(".\\document\\Литература.docx", "rb") as f:
if query.data == 'button3':
await query.message.answer_document(f)
если у вас линукс то замените \\ на /