My daughter haa behavioural issues and her ages is 14 years and does véry naughty things

Ans: Kindly involve her in games , physical activities more .
Use her energy into some thing more positive like activities .
You can stop giving her the screen time.

Ans: Talk to her with a non judgemental space.
Ask her about how she feels like when with her peers .Start with gratitude journal as a routine in the house for every one,by modelling it your self. Do not do direct talk but can be a indirect way of putting it to her. Give her social praise if she attempts this. The praise can act as a reinforcing thing to get her do better.

Ans: Please consult a good child psychologist to screen for dyslexia

Ans: Hello!!
The addiction to mobile after COVID is a menace every parent is facing. The good part is she is aware about her exams and studies at least one week before her exams.

The rude behaviour, lack of focus on studies is all stemming from the mobile games. They are highly addictive and the thrill they give is beyond imagination. Slowly but surely you have to take away the mobile from her, that's the only way to help her look for other sources to keep her busy .Friends, new skills and studies will get her attention only when the mobile is away.

Allocate time for food, sleep, studies, play time and also mobile time( can't just take away the mobile, has to be weaned away from it gradually), in a day. Set a timer for the mobile usage, she has to return the mobile as soon as the timer bell rings.

Pls remember you are the adult here, she is just a child. Guide her, lead her towards better and interesting things to do. You all as a family have to stop sitting with the mobile, start reading books ,play board games , learn a new skill, sing songs, cook together, bake together, you make everything at home an interesting activity, joyful activity, why will a child sit on the mobile?
It is a going to be lot of hard work for you and if the end result of this is seeing your daughter away from the mobile, laughing and talking to her friends, playing around, studying well.....then this is worth all the effort.