ItsTooHard puzzle show answers?

you cant. The puzzle website is independant from these give aways. So there is no time limit on the puzzles.

Either you manually write the answers yourself on the forum, or if you were logged in into your account while making the puzzle, go to your account and you could view solutions. Share that link.

You could just post the answers in the forum. Or, if you created the puzzle while logged in with an account, you could edit the puzzle so that the answer is either in the hints or the question. If you created it with an account then there is a link that allows you to view the solutions to your own puzzle. You could try sharing that link with someone to see if it works for them, I'm not sure if it will. The last way would allow you to offer the solution without modifying the main puzzle, if it works that is.