Hello! First thing. This deal is extremely YMMV. Just getting that out of the way now. Again. Very YMMV.
Ok, with that out of the way 😁
YMMV 1: You must have bought a Microsoft Surface, presumably from Microsoft Store directly (they occasionally have these "loyalty" deals, if you will)
YMMV 2: You must get the email from Microsoft titled "three days only - 20% off select Surface devices" to get your UNIQUE, ONE-TIME code
YMMV 3: You must want to purchase a Surface Laptop 2 or Surface Studio 2. Surface Laptop, a solid ultrabook design but commonly on sale so ok but not great deal, unless you want a more powerful model since the deals usually focus on the base / lower models.
HOWEVER, if you look at the Surface Studio 2, the offer is good for $960 off the top model ($4799). The Studio 2 (any model) rarely is on sale especially brand-new, and is not for everyone. Say it with me "The Surface Studio is not for everyone". This is a above-premium concept device specially tailored for professional artists, designers, etc with its insane screen and design. There are also a number of devices released or soon to be released that are inspired by some or all of the Studios features for less.
BUT, if you are someone who knows all this, wants this Surface Studio 2 and has purchased a Surface previously, this is a great and rare offer for an incredible device. Hope this helps and I am happy to offer any info I can!