I'd recommend to use the latest (newest) extraction.
Std. core supply voltage is 1.8V ± 10% , but usable down to 0.9V . But there are also 0.18 um TSMC model files, which additionally include 3.3V devices.
You may want to check this on your own: if there are only 2 models (NMOS & PMOS), these are the models for the standard supply voltage. If 3.3V MOSFET models are given, this will be explained in the comments.