@safekumi yes as it says in the link EarBuds are sent 15-30 days after purchase automatically . It is not a Samsung promotion. However you would need to have purchased the S23 Plus by 16 March as shown here https://eu.community.samsung.com/t5/galaxy-s23-series/how-do-i-claim-my-free-ear-buds
I do not work for Samsung or make Samsung Products but provide independent advice and valuable contributions.
My Device- S21 Ultra 5G ( SM-998B/DS ) CSC= BTU , 12GB/256GB
One Ui 5.0,Android 13 .