VIX options are cash-settled — no shares, ETF units, or futures contracts change hands. At expiration, the OCC automatically exercises any in-the-money contract and credits or debits cash to your account the following business day.
The settlement ticker to watch is VRO, this is the official VIX settlement price published by CBOE on expiration morning. VRO will often differ from the prior night's VIX closing level.