Do precum have the capability to make a woman pregnant?

All secretions of an excited penis have enough sperm to cause pregnancy. (the main ejaculate is more likely to) All these secretions need to do is attach to the mucous linings of the female genital tract, once in/on, they can swim up to the cervix and lead to pregnancy. It would be rare and truly unlikely for this to happen, but it could.

Yes. If you do not wish to be pregnant, use contraception all the time, every time. You may consider implanted contraceptive, or IUD. Practice safe sex: https://www.hopkinsmedicine.org/health/wellness-and-prevention/safer-sex-guidelines Get HPV vaccine.