Earlier, the congress reverted the Executive Policy Council to Secretariat, undoing the 2016 decision that created the council.
Biden, who will take office on January 20, is unlikely to hold direct meetings with Kim unless the North Korean leader takes significant denuclearisation steps.
Kim always dons civilian dress for public appearances and it is the first time he has been shown in uniform since he inherited power following his father's death in December 2011.
Kim will likely use the Workers' Party congress as a venue to muster a stronger unity and lay out new development goals for the next few years.
Kim put himself in front, reaffirming his commitment to developing nuclear weapons and announcing an ambitious economic development plan.
Some experts say North Korea may be putting pressure on South Korea in order to benefit from an economic engagement as the pandemic is aggravating North Korean economic woes.
South Korean Foreign Minister Kang Kyung-wha said over the weekend that it's hard to believe North Korea's claim that there has been no virus outbreak on its soil.
The sanctions have hit North Korea's economy hard, creating even more hardship for citizens outside of major cities.
North Korea has maintained no single virus case has been found on its territory, a claim widely questioned by outside experts.
The North Korean government has ordered diplomats overseas to refrain from any acts that could provoke US as it's worried about President-elect Joe Biden's possible new approach.
Chinese state-backed hackers have also been targeting vaccine-makers, the U.S. government said in July while announcing criminal charges.
Trump's bizarre diplomatic engagement with Pyongyang veered from mutual insults and threats of war to "love letters" and the first-ever meeting between a sitting US president and a North Korean leader
Kim as saying that Komdok’s typhoon-related damage was “more severe than he thought” and praised soldiers mobilized in rehabilitation projects for their devotion.
Ties between the Koreas remain strained amid the deadlocked nuclear diplomacy between Pyongyang and Washington.
Meanwhille, Kim also received a congratulatory message from China President Xi Jinping on the 75th founding anniversary of the WPK.