"It is our view that the high voter turnout is indicative of sound voter education and publicity", said Zimbabwe Electoral Commission (ZEC) chairwoman Priscilla Chigumba at a media briefing in Harare late Monday.
President Emmerson Mnangagwa, Mugabe's former right-hand man in the ruling ZANU-PF party, faced off against opposition leader Nelson Chamisa of the MDC (Movement for Democratic Change) in the historic vote.
Out of Zimbabwe's 5.6 million registered voters, half are under age 35.
Mugabe, forced out under military pressure, had declared he would not vote for the ruling party he long controlled and called Chamisa the only viable candidate.
Each polling station must post its results outside after vote-counting, she said.
A run-off vote is scheduled for September 8 if no presidential candidate wins at least 50 percent.
Mugabwe, who led the country from its 1980 independence, was ousted in November after being blamed for ordering violence against his own citizens, squashing free speech and rigging elections.More news: Cohen says Trump knew of 2016 Trump Tower meeting ahead of time
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In Harare, 32-year-old finance graduate Tinashe Dongo said he wanted "change" following Monday's vote.
There remained concerns about bias in state media coverage of the election, a lack of transparency in ballot printing and reports of intimidation by pro-government local leaders who are supposed to stay neutral.
Meanwhile, a monitoring group, the Zimbabwe Election Support Network, issued preliminary findings on the vote, noting improvements such as a biometric registration system that reduced the chances of fraud.
The contenders in Zimbabwe's vote must accept the results and "should look at the larger picture of success - a successful election for Zimbabwe", he said.
This comes after Zec acting chief elections officer, Utoile Silaigwana confirmed that the MDC Alliance presidential candidate had been reported to the police for holding an illegal press conference on Sunday at Meikles Hotel after the deadline for political campaigns.
The Zimbabwe Electoral Commission says it will release the final tally within five days. "We have done an impossible thing".