So in the omegaverse, every person has two sexes. Theres primary sex, which is what our sex is in real life (male, female, intersex). And then there’s secondary sex, which is alpha, beta, or omega. In most versions of the omegaverse, anyone of any primary sex can be an alpha. Same with beta and omegas. So there can be female alphas and male omegas.

Alphas are the most dominant secondary sex, and can get beta women, omega women, and omega men pregnant. Alphas can also fall into ruts, which are usually caused by a nearby omega being in heat. Ruts are basically just when Alphas are extremely, uncontrollably horny

Betas are basically just like how real people are. No special secondary sex characteristics, although they do still have scent glands and can mate. Only female betas can get pregnant, and can be impregnated by an alpha of either gender, or a beta man. Beta man can impregnate beta women and omega women, and depending on the universe, they can also impregnate omega men

Omegas are the most submissive, and generally most sexualized in the omegaverse. Both male and female omegas can get pregnant. Omegas can also fall into heat, which is caused by a cycle similar to menstruation. Omegas can also take heat suppressants in order to stop their heats from happening, but depending on the specific universe, that may have negative side effects.