Wireless access points don’t always encrypt data specifically.
If the access point is configured without encryption then the connection will not be encrypted.
If the access point is configured for encryption then as the data flows from the wired network through the access point the data will be encrypted over the air. The access point at the other end (or computer with a wifi card) will then decrypt the data and send the unencrypted data over the hard wire network.
Data can be transmitted over the hard wire network as well using IPSec.