Is it permissible for a girl to join a mixed team (males and females) to write university lectures in order to obtain them for free, with the possibility of speaking with them in the future out of necessity, if she cannot afford to buy them and her father is unable to do so, and she faces difficulty studying from a mobile phone?

University studies and degrees are an urgent necessity that alleviates hardship and difficulty, and Islamic law came to remove hardship. Therefore, what was prohibited to block a means (sadd al-dhari'ah) is permitted by a legitimate need. So, it is permissible for a Muslim to remove hardship from themselves, even if it involves some mixing or speaking with the opposite gender out of necessity. However, the necessity must not be exceeded, and one must refrain from whatever can be refrained from. Speech should be appropriate, without softening the voice, and private seclusion with any men should be avoided, while maintaining the legal hijab and making God one's overseer. If there is a fear of temptation, one must leave the group.