The majority of public buses have stepped entrances. This includes the No1 & No2 that go to Porta Ventura. However there were a few newer buses on the No4, which goes from La Pineda to Cambrils, which have wheelchair symbols but still have steps

We always folded up our pushchair, as buses get very busy.

BTW if theres a red PLANA bus kiosk at your local bus stop, you buy your bus tickets there, rather than from the driver.

We've always folded down our stroller type buggy on the buses as they always seemed busy. Never seen any buses for buggy's but then we would have just folded it down or grabbed a taxi.