The relief of Africa has been formed by multiple different types of forces, over long periods of time, and in different periods of time.
The plateau in the central part of the continent is the oldest crust of the continent. It is the African Shield, and it has been there foe hundreds of millions of years, created initially by the volcanic activities in the distant geologic past.
The Atlas Mountain Range in the northwestern part is a result of the collision of the Eurasian plate, and it is a relatively new feature.
The Eastern highlands have been formed by volcanic activity in the past, but also in the more recent time, the rift valleys that are forming are due to the divergent plate boundary, as the eastern part of the continent is separating from the basis.
The Congo Basin and the surrounding area have been heavily influenced by the erosion, as the heat is constantly there, there's almost daily precipitation, and the rivers have done there job as well.
