How can I help a friend who does not pray regularly, listens to music, accompanies a bad friend and refuses to abandon her, communicates with foreign young men, and adorns herself and wears perfume when going out, while refusing advice?

Mixed-gender education is forbidden and causes corruption in society. One should avoid places of mixed-gender interaction in study and work. As for your friend, your duty is to advise her and remind her of Allah. If she responds, then praise be to Allah. If she refuses, then Allah the Almighty said: ﴿The Messenger's duty is only to convey the message﴾ and ﴿And remind, for indeed, the reminder benefits the believers﴾ and ﴿So remind, for you are only a reminder. You are not over them a controller﴾, and ﴿O you who have believed, upon you is [the responsibility for] yourselves. No one who errs will harm you if you follow the right guidance.﴾ You must seek righteous company and avoid evil gatherings and bad companions, for Allah the Almighty said: ﴿And He has already revealed to you in the Book that when you hear the verses of Allah being rejected and ridiculed, do not sit with them until they engage in another conversation. Indeed, in that case, you would be like them. Indeed, Allah will gather the hypocrites and disbelievers in Hell all together.﴾