How to Play 2-Player Online in WWE 12 — You Can't

Impossible. WWE '12 (2011) has no online multiplayer on any platform. Only local (split-screen / same console).

Online WWE Games Timeline

• WWE 2K14 (last 360/PS3) — servers shut down 2017
• WWE 2K15–2K20 — servers dead
• WWE 2K22 / 2K23 / 2K24 (PS4/PS5/Xbox One/Series X|S/PC) — active online (Ranked, Casual, Universe, Creations)

For online wrestling today: WWE 2K24 or AEW: Fight Forever.