By transit, the usual way from downtown Vancouver to Langley is the Expo Line to King George Station in Surrey, then a bus. By road it is about 50 km and 60 minutes, though traffic changes that a lot.
Expo Line to King George
Board the Expo Line downtown, for example at Waterfront Station, and take the train marked King George. The ride from Waterfront to King George takes about 39 minutes. The line splits at Columbia Station, so check the sign on the front of the train before boarding.
The 501 bus to Langley
At King George, the 501 runs between King George Station and Langley Centre. That leg takes about 45 minutes. Other routes also serve Langley, including some from Carvolth Exchange, a transit exchange on 202nd Street that several bus routes use. Which one suits you depends on where in Langley you are going, so enter the exact address in the TransLink trip planner. It also shows current times, which change between weekdays, evenings and weekends.
Pay with a Compass Card or tap a contactless card so transfers between train and bus are covered. Fares depend on zones, so check TransLink for the current price.
Adding the two legs, the 39 minute train ride and the 45 minute bus ride, gives well over an hour once you count the transfer and any walking. That is longer than driving in light traffic, but it avoids parking and the bridge queues. Langley covers a large area, so a destination far from Langley Centre can need a different bus than the 501.
Driving or taking a taxi
Driving gives you a personal schedule and avoids transfers. Rush hours leaving Vancouver can add a lot, and weather or roadworks can too, so a quick look at live traffic helps.
For a late arrival or with luggage, a taxi is practical. Compare options in the Uber estimate calculator or the taxi fare estimator, and see the Vancouver taxi page to book from the city.