Every time I have bought a house, the property taxes are paid by the buyer and the seller. The property taxes are prorated. This means they are divided according to the time the seller has been in the house for the year it is sold.
Simply put, if the seller has been in the house for 6 months, they will have to pay 50% of the year’s property taxes.
Usually, the seller DOES NOT have to come out of pocket to pay the taxes. Instead, the cash from the sale of the house is used. The seller then gets the remaining amount.