To keep your neckties in good shape, you should always untie and hang them. It's best to untie your tie by reversing the process. Don't just pull the small end out. To uncrease your tie it's usually enough to just untie and hang it overnight. If there are still some creases, you can try this: roll your tie up from the small end and leave it for like a day- hang your tie in the bathroom while you shower, the steam helps to remove creases- steam your tie with medium heat iron.
Woolen ties and bowties also don't crease much. They have to be dry cleaned, you can steam and iron it gently with medium temperature iron.
Cotton ties are best with casual outfits and they are going to crease, it's a part of their charm. It's best to dry clean them also, but they can be handwashed at 30°C. Do not wring the tie, just tap it dry with a towel on a board and let it dry. You can steam and iron it gently with medium temperature iron.
Cotton bowties can be handwashed, iron at medium temperature.