That's a standard NEMA 14-30 receptacle and 4-prong plug. You need 4 prongs/wires, not 3, because neutral needs to be separate from safety ground, like it is for every other appliance in your house.
3-prong connections date back to before grounding (so, like, before 1960) and a temporary exception granted to dryers and ranges that they didn't need to come into modern (1960s) codes. The logic is these connections are rarely disturbed, so a neutral contact failure is unlikely, even though this would guarantee that the chassis of the machine is electrified. Anyway, you don't want that.
I'll be the first cheerleader for using parts of known quality from a vetted source; however, LOL, dryer cords are commodities and you can use any sold at a retail store. There's a nasty virus going around so I'd order delivery or "curbside pickup" from Home Depot or Lowes.
Whenever you're dealing with a stackable, watch your plugs and sockets. Some apartment and condo developments use very particular models of washer-dryer that let them reduce the number of circuits and utilities they must install in each laundry room. Strategies include:
- Electric to eliminate a gas line, obviously.
- Specifying a heat pump (condensing) dryer to eliminate dryer vent
- Specifying stackable washer-dryer pair that are custom-matched, so the washer takes power from the dryer's NEMA 14-30 plug, eliminating need for a 120V circuit in the space
The last two can "bite" people in such developments, who presume they can replace a washer-dryer stackable with "any old thing". Only to find there is no dryer vent, or no 120V power.