H4 to F1, is green card process still valid with existing H4?

[ask4kk]

Hi
My daughter is in H4 visa and going to college for undergrad. question
1. should I change her visa to F1?
2. If she got F1, would her green card process currently going with H4 cancel ?
3. if not greencard affected, should visa has to covert back to H4 when applying green card?
4. can she study undergrad/grad with in H4 visa or without F1?

please help.

thank you