How do you finish floating floor around doorways?

Remember that floating floor must NOT be secured or nailed at any point.

The easiest way to finish around all the nooks & crannys of a door facing is to undercut the casing & slide the board under, will look like a pro did it !!

Little trick of the trade is to take a scrap of laminate lay it face down & then lay a handsaw on top of the scrap, using it as a gauge for thickness and support for the saw.

If the question is about the transition from one flooring to the next, that's what all those expensive transitions are for. The home centers and many in stock dealers have them on hand.