I have been tasked with finding a certain flower and I have tried searching the internet with no luck. I am searching for a flower I am assuming is common that originates from Africa but only has one petal does anyone know what this could be?

Nope. Sorry. Tried my sources and nothing came up. I think whoever tasked you with this is pulling your leg.

I, too, have searched. Supposedly, there is a variety of one kind of flower that has only one petal, but photos show otherwise.

They might be thinking of flowers like Calla Lilies that have a specialized leaf (bract) that can look like a petal but isn't. In the Calla Lilies case, the bract is the cone shaped leaf that surrounds the center stalk of small flowers.

There are some flowers that do have a larger petal that "hides" the smaller petals. One is the flower of the Erythrina, a tropical tree (Coral Tree and Flame Tree are two common names). It has one main petal that surrounds smaller petals.

Did the person give you any other identifiers than 'one petal'?