Are we commanded ’’when’’ to wear them? Are we to wear them all the time and let them be seen all the time? Should women wear them?
The Torah (Numbers 15: 39) writes in regard to the Tzitzit “and you shall see them” from here we learn that only during the day the obligation applies. There is a dispute among the early rabbinic authorities whether this means day time or day clothes (excluding night wear). We follow both opinions and do wear our Tzitzit at night till we go to bed. Only a four cornered garment is required to have the Tzitzit strings, however, since we nowadays we have a rather different dress code, we wear a special four cornered garment under the shirt so we don’t miss out on this precious Mitzvah. Women don't wear Tzitzit since they are exempt from time-bound positive Mitzvot.