One embodiment according to the present specification relates to a method for constructing a preamble in a wireless LAN (WLAN) system. According to various embodiments, a PPDU may comprise a first signal field and a second signal field. The first signal field may include first information about PHY version. The first information may be determined on the basis of whether the PPDU is an EHT PPDU. The second signal field may include second information about the transmission of the PPDU, which is set on the basis of the first information.