Can I say catch the bus?
Can I say catch the bus? Catching a bus describes the process of getting to a stop/station, waiting and boarding. Taking a bus describes the entire process, including the journey itself.
Is take a bus correct?
There contexts where the indefinite article “I take a bus” could also be appropriate, e.g., “I take a local bus from my neighborhood, and then transfer to an express bus.” But in most contexts, in “I take the bus” , 'the bus' refers to that mode of transportation, not to a particular vehicle.