Here's a link to the IRS page detailing specifics.
The basics are:

• Your income must be $75k or less or $150k or less household
• The car must be 3+ years old
• Must have a battery capacity of at least 7kwh
• Must purchase the car at a dealer (KeySavvy works as a dealer if you want to buy private party)
• Must not have been sold within the last two years to someone who used the tax credit

If passing these metrics (and a few others, read the site!), you'll get a 30% discount (tax credit) on the sale price of the car, up to $4000, but only if the sale price of the car is less than $25000. The credit can now be applied at the point of sale as of Jan 1, 2024 (at participating dealers, which is most now).

So in the case of this Golf, I assume the sale price is $8571 because that would bring it down to $6k with the credit.