Salam! Please is it permissible for a male guy to wash clothes of a married woman?

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.

In principle, it is permissible for a man to wash or sew the clothes of a non-Mahram (marriageable) woman whether or not she is married. It is also permissible for a woman to wash and sew men's clothes.

Allah knows best.