Both sides looked nervy in the opening stages, with the Southern Africans repeatedly trying to play in Temwa Chawinga with early balls forward – a tactic that worked well in their semi-final victory over Algeria.
The opener came after Sikelo misjudged an Eto cross from the right and Grace Mendoua’s header back across goal was tipped on to the bar by the Malawi keeper.
Ngah Manga was on hand to pounce on the rebound from two yards out and Cameroon, ranked 82 places above their opponents, never looked back.
The Indomitable Lionesses doubled their lead when Malawi failed to clear a corner and Eto pivoted before sending her first-time effort into the bottom right-hand corner.
Sikelo was arguably at fault for the third as she decided to come off her line in an attempt to cut out Genevieve Ngo Mbeleck’s through ball but Eto beat her there, got to the byline and crossed for Ngah Manga to head into an empty net from two yards.
Valentine Nguele only took charge as Cameroon coach in June but has built a well-drilled side which upset Nigeria 1-0 in the quarter-finals and then beat host nation Morocco on penalties in the last four.
Bihina was the star in both of those matches, pulling off nine saves against the Super Falcons and then keeping out an extra-time penalty and three more spot-kicks in the shootout against the North Africans.
The 22-year-old Benfica goalkeeper was rarely called upon in the final as Malawi’s challenge faded.
Cameroon came close to adding a fourth late on but an Eto strike from a narrow angle was well saved by Sikele before Mendoua headed a corner across goal and wide.
In injury time Indomitable Lionesses substitute Gabrielle Onguene tapped in but the 37-year-old was to be denied by the offside flag and booked for taking off her shirt in celebration.
Cameroon football federation president Samuel Eto’o celebrated each goal wildly in the stands at the Moulay Hassan Stadium and the Cameroon bench and officials ran on to the pitch on the final whistle to mark their first Wafcon crown after final defeats in 2004, 2014 and 2016 – which all came at the hands of Nigeria.