The former Azzurri captain was appointed on Wednesday after Fabio Caserta was relieved of his duties.
Caserta was sacked on Tuesday following back-to-back defeats to Cagliari and Brescia.
Cannavaro takes charge with Benevento 13th in the second tier of Italian football, and his first game at the helm will be against Ascoli on October 2.
The 49-year-old's last role was with Chinese Super League side Guangzhou, and he had a brief spell as China boss in 2019.
Cannavaro will be presented to the media at Palazzo Paolo V at 5pm local time on Thursday.
Iniesta, now playing for J1League outfit Vissel Kobe, celebrated his 36th birthday on Monday.
The former Spain international left Barcelona in 2018 after a trophy-laden stint with the LaLiga giants.
Cannavaro, who won two LaLiga titles as a Real Madrid player, said he always had eyes on Iniesta, widely regarded as one of the best midfielders of all-time.
"He played with such style, you couldn't help but love him when you saw him play," the Italian told AS.
"He was a perfect professional, very humble... I loved him.
"Everybody might have been watching Messi but I was watching Iniesta."
The reigning European champions could not top their World Cup qualifying group, leaving them having to beat North Macedonia in the playoffs semi-final on Thursday to keep their hopes alive.
Italy would then have to bypass either Turkey or Cristiano Ronaldo's Portugal in the final to secure their spot at Qatar 2022, which means one of the previous two European Championship winners will not be present at the World Cup.
Robert Mancini's reinvigorated Azzurri responded to failure to qualify for FIFA's showpiece event in 2018 by lifting the delayed Euro 2020, and Cannavaro explained that it is vitally that they find a way through this year.
"Between us and qualifying for Qatar there could be Portugal, but also Turkey would not be a walk in the park," Cannavaro, who won the World Cup in 2006, told Italian newspaper Il Mattino.
"And even before that in Palermo, we must beat [North] Macedonia. We threw away a chance in Rome against Switzerland [in the group stages], there is no way we can not qualify for the World Cup for eight years.
"It would be a disaster for everyone. Mancini will find the resources to be able to qualify."
While Italy push for World Cup qualification, Russia will not be featuring in Qatar after FIFA excluded them due to the ongoing invasion of Ukraine, a decision Cannavaro supports.
When asked if FIFA had made the right call, he added: "Yes. Football is not a world apart. It had to give a signal and it did."
Maradona and Messi are both regarded as two of the greatest players and the Argentine duo's standing atop football's history is often debated.
Messi is a record six-time Ballon d'Or winner but former Italy defender Cannavaro believes 1986 World Cup champion Maradona is the greatest.
"I respect Messi a lot. For the new generation he is one of the best, but Maradona is different because the football was different," Cannavaro – now head coach of Chinese Super League giants Guangzhou Evergrande after captaining Italy to World Cup glory in 2006 – told Sky Sports.
"They kicked him a lot, but he was always in control and he was tough.
"Messi is top, but Maradona is another world. I never compare him with other players. I never saw Pele, but I watched Maradona, for seven years I saw every game.
"He's not one of the best, he's the best."
Maradona won silverware at Barcelona, helping the Spanish giants to Copa del Rey, Copa de la Liga and Supercopa de Espana glory.
The 59-year-old then went on to become an icon with Napoli, where he won two Serie A titles, as well as UEFA Cup, Coppa Italia and Supercoppa Italiana.
Messi has won 10 LaLiga crowns and four Champions League titles among other honours at Barcelona, though he has not tasted senior success with Argentina.
Sport has been brought to a standstill due to COVID-19, with Serie A, LaLiga, Bundesliga, Ligue 1 and the Premier League all on hiatus.
The Champions League and Europa League finals have also been postponed, with Euro 2020 pushed back to next year following more than 18,800 deaths worldwide – over 9,800 of the casualties from Italy and Spain.
Former Italy, Juventus and Real Madrid defender Cannavaro – now in charge of Chinese Super League powerhouse Guangzhou Evergrande – is not confident that football will resume by May.
"In less than a month it is not known what is going to happen in the world," the 43-year-old told COPE.
"I think it will take a long time for this to end in Italy and Spain.
"It will be difficult for European football to return before the season ends."
Cannavaro has been based in China since joining Evergrande in 2014 before returning in 2017, while he was briefly in charge of the national team last year.
China has enforced strict measures to combat the spread of coronavirus, which originated in the country and has claimed more than 3,270 lives.
"The virus in Guangzhou is under control and life is beginning to go back to normal," Cannavaro added. "There are no more restrictions, only 14 days at home.
"In two days, I finish my quarantine. All of us who come back have to do it.
"Staying at home is essential because we do not give the virus the opportunity to infect more people.
"We have to learn from China, they have more experience in this situation."
The 22-year-old was named UEFA's Player of the Tournament for his penalty shoot-out heroics in Italy's victory over England in last Sunday's final at Wembley.
Donnarumma kept out efforts from Jadon Sancho and Bukayo Saka, after Marcus Rashford had earlier hit the post, as Italy ended their 53-year wait to win a second Euros crown.
He has won all five of the shoot-outs he has been involved in for club and country, having also made a crucial save in the semi-final shoot-out victory against Spain.
Italy legend Cannavaro believes Donnarumma answered any of his remaining critics with his displays at Euro 2020 and expects his compatriot to shine for at least the next decade.
"Donnarumma is the real champion of this Azzurri side," Cannavaro told Tuttosport. "I am surprised that, before the Euros, some people thought he was an average goalkeeper.
"There's nothing average about Gigio. Just think of the tranquillity he has at 22. He will be the best goalkeeper for the next 10 to 15 years."
Donnarumma played more minutes at Euro 2020 than any other player (719), missing only the closing stages of Italy's win against Wales in the group stage.
After spending time celebrating the Azzurri's triumph, the young keeper this week completed a free transfer from Milan to Paris Saint-Germain, where he will compete with Keylor Navas.
"At least we will enjoy him with the national team," Cannavaro added.
In his final season at San Siro, where he has spent his entire senior career to date, Donnarumma recorded a joint-high 14 Serie A clean sheets alongside Inter's Samir Handanovic.
While Italy ended a long wait for continental silverware last week, Argentina did likewise by claiming their first Copa America crown since 1993.
Lionel Messi was the star performer for Argentina, scoring four goals and assisting five more to win his first trophy at international level.
Despite Donnarumma's impressive displays for Italy, Cannavaro is backing Messi to win a record-extending seventh Ballon d'Or crown later this year.
"He is the absolute number one and he was the protagonist of a great Copa America," Cannavaro said.
Mbappe, 21, continues to be linked with a move to Madrid from PSG, where he has starred during the past three seasons.
Madrid have found it hard to replace Ronaldo, who decided to leave the LaLiga giants and join Juventus in 2018.
Cannavaro, who won two LaLiga titles with Madrid as a player, said Mbappe could be the player the club need to follow what Ronaldo delivered.
"Real Madrid need players like Mbappe, a young star who could follow in the footsteps of Cristiano Ronaldo," the Guangzhou Evergrande coach told AS.
"It's normal that Madrid want to sign him but it also has to be taken into account that PSG's owners don't need the money. They are ambitious and they want to win the Champions League.
"I think it will be difficult for Madrid to get him. The president of PSG is a person who wants to win, I know them well and they will fight tooth and nail to keep Mbappe."
Mbappe has won three Ligue 1 titles, a Coupe de France and a Coupe de la Ligue with PSG.
He scored 30 goals in 33 games in all competitions this season, with the Ligue 1 campaign cancelled due to the coronavirus pandemic.
