The American, 34, won three out of four Grand Slam titles last season.
"This is probably the best slam I've played in a year," said Williams, who can match Steffi Graf's Open-era feat.
Britain's Jamie Murray is in the men's doubles final, while compatriot Gordon Reid competes in two wheelchair finals.
Murray, whose brother Andy plays Novak Djokovic in Sunday's men's singles final, takes on Daniel Nestor and Radek Stepanek alongside new Brazilian partner Bruno Soares.
Murray parted ways with Australian John Peers at the end of 2015 after the pair finished as runners-up at both Wimbledon and the US Open.
Fellow Scot Reid is attempting to lift the men's singles and doubles title, competing alongside Japanese partner Shingo Kunieda after he plays Belgium's Joachim Gerard earlier in the day.
Williams will be the centre of attention, however, as she bids to match Graf's Open-era haul of 22 Grand Slam titles, closing in on Margaret Court's all-time mark of 24.
After a tricky first-round encounter against Camila Giorgi, she has been progressed through the draw with a series of emphatic victories, dropping just 17 games and no sets in the next five matches.
She beat five-time Grand Slam champion Maria Sharapova 6-4 6-1 in the quarter-finals before seeing off fourth seed Agnieszka Radwanska 6-0 6-4 to make the final.
"Even if I don't win, I really can take away that I've been really consistent and I want to continue that," Williams added.
German seventh seed Kerber is playing in her first Grand Slam final, compared to Williams' 26th.
The 28-year-old has won just once in six previous meetings - a 6-4 6-4 upset in Cincinnati in 2012 - but believes her status as the underdog and the belief built by a steady climb up the rankings gives her hope.
She will be ranked at least fourth in the world after the tournament and will move as high as number two if she wins.
"I don't have so much pressure like she has. I know I can lose the match. That's why I'm going out there to try to win it," she said.
"I think I grow in the last few years to be a top-10 player.
"Now I'm back in the top five. I think I showed everybody that I deserve it. That's a good feeling."
Serena Williams says she is playing near her best as she attempts to win a record-equalling 22nd Grand Slam title when she faces Angelique Kerber in Saturday's Australian Open final.