Is viewing other female students' results by obtaining their university ID numbers, which are available online, along with a unified password, considered a form of spying (tajassus), and what should I do regarding this action?

It is forbidden to spy on Muslims and to seek out their private matters and secrets, as Allah Almighty says: "O you who have believed, avoid much [negative] assumption. Indeed, some assumption is sin. And do not spy," and the Prophet, peace and blessings be upon him, said: "Beware of suspicion, for suspicion is the falsest of speech. And do not spy." So, if students do not wish for their academic results to be known, it is not permissible to seek them out. One must repent from such actions and seek forgiveness from those who were spied upon, if possible, without causing further harm.