A healthy sperm must fertilise an egg in a fertile woman’s Fallopian tubes in order to result in pregnancy.
Of course, an erect penis ejaculating within a vagina is the nearly universal technique of achieving this, and it is responsible for 99.999% of pregnancies.
Hence, in this situation, the “transman,” or, to put it another way, a woman who identifies as a man, would not be able to become pregnant since she does not generate male gametes, or sperm. Also, they lack the gonads necessary to deliver them.
If a person generated male sperm and had a functioning penis, they would be biologically male and would not be considered transgender. Gametes in humans determine sex.
Even in cases of real hermaphroditism, which are incredibly uncommon a person who produced both viable gametes would almost probably not be able to deliver those gametes (although it is, in theory at least, possible for an intersex person to impregnate themselves, albeit with horrific genetic ramifications, and only 11 cases are known in history ). Furthermore, there are no intermediary gametes between egg and sperm, as there would be if being intersex were the trans activists’ invented “gender missing link.”
Thus, in response to your inquiry, no. Unless she is using a turkey baster or some other device, a female cannot get another female pregnant.