We have been to Uni several other times, but not during this mess called Covid, lol. EP (Express Pass) came with our hotel stay, since we are at Hard Rock. If you are asking about EP itself, you can get it for free when you stay at Hard Rock, Portifino (closed at this time) or Royal Pacific. Otherwise, you can purchase the pass seperately at the park.
Just to give you an idea about EP--we have hit BOTH parks in a single day by utilizing EP. Typically, we start our vacation at Uni, then head to Disney for the rest. We have hit literally every ride we have wanted in 1-day (of course that is moving pretty good) by using EP. I wish Disney had something similar, because this is where Uni is far superior.