Why not read the article? Here you go:

Until recently, most cases in Congo resulted from consumption of contaminated meat or close contact with infected animals and people. But last year, scientists discovered a new subtype of mpox, Clade Ib, which appears to spread from person to person primarily through heterosexual transmission.

From a recent BBC article:

Mpox is transmitted through close contact, such as sex, skin-to-skin contact and talking or breathing close to another person.