In a house the pad is in a utility room. In an apartment it's in your living room, and that changes which problems matter.
Odour stops being someone else's problem
A pad in an open-plan flat is a few metres from where you eat. Timing matters more than any cleaning product: wash it soon after use rather than letting it sit, since a pad left soaked for days is the one case where smell genuinely lingers. A splash of white vinegar in the rinse handles most of the rest.
How it looks is a real requirement, not vanity
Something you see every day in a room you live in is furniture, whether or not it was sold as furniture. That's the reason these are printed rather than white. Darker prints show less between washes, busier prints hide the everyday marks, and plain grey stays quiet in a room that already has a lot going on.
Which size
28 x 32 in (71 x 81 cm) fits an apartment corner without taking a walkway. Measure the spot before choosing, because in a small flat the constraint is usually the floor, not the dog.
Placement
Away from food and bedding, somewhere with a clear path from wherever your dog sleeps, and somewhere you won't move it. Moving it is what breaks the habit.
The prints are on the washable pee pads page, and washing is covered in the care guide.