There isn't any specific position that can make you pregnant.
If you are at the right time of your cycle and ovulating and your partner has no problems with his semen count, you do not need to worry about sexual positions. Important thing is to enjoy the act of lovemaking and the intimacy you share with your partner.
If you have been trying for a time and nothing is happening, and especially if you have been keeping a diary of your ovulation time so that you make love when you are the most fertile, make an appointment to see your doctor.
The doctor can do blood tests and other tests to make sure that there is nothing wrong with you. Women who have polycystic ovaries have difficulty in conceiving. Sometimes a man may have a low sperm count, and you partner may need to get that checked out.
Having said all that, after sex, you could put a pillow under your bottom to raise that part up so that the semen do not come down so quickly. But if you and your partner have no problems with your reproductive parts, then it will not matter with regard to what position you were in.
Probably man on top. Pamela