Dhanteras in the year 2020 was observed on Friday, November 13. It is celebrated on the 13th lunar day of Krishna Paksha in the Hindu month of Kartik. The puja muhurat (auspicious time for worship) on that day was from 5:28 PM to 5:59 PM approximately, and the occasion marks the beginning of the five-day Diwali festivities. People traditionally worship Goddess Lakshmi and Lord Kubera, and it is considered auspicious to buy gold, silver, or other valuable items on Dhanteras as a symbol of wealth and prosperity.
For comparison, Dhanteras in 2025 is on October 18, but the specific question was about the year 2020 so November 13 is the precise date for that year.