As long as both borrowers and borrowers recognize that it is a word with no different meanings, its legal effect will not be affected. The problem is that both sides admit this, and no one can guarantee that one of them will go back on his word and not admit it. For example, the person who wrote the iou said that it was originally a thousand words, because one side can only add a thousand words to write a thousand words, but one side can't add a million words at all. Therefore, after discovering the problem, it is better to rewrite it in time when both sides still admit that it is a million words.
As for not writing the date, it is impossible to determine the repayment period and calculate the interest, and the borrower may also encounter some troubles when repaying.