Is it obligatory to wash clothes if a daughter urinates on them, and the urine does not transfer to the mother's clothes, and the mother does not see anything apparent?

If your daughter's clothes, which are soiled with urine, touch your wet clothes, the impurity transfers to them, and it becomes obligatory to wash whatever parts were affected by the urine. If the exact spot is not clear, you must wash the part that is most likely to have been contaminated. However, if you are unsure whether the impure spot was touched, nothing is required of you, as the original state is purity.