In Namibia, low-literacy rates pose significant challenges to digital literacy initiatives. A comprehensive search of academic databases and grey literature was conducted, with articles screened using predefined inclusion criteria. The review identified a need for simplified UI designs that cater to illiterate users, emphasising clear visual cues and simple interactions over text-based instructions. Current user interface design practices often overlook the needs of low-literacy populations in Namibia. The reviewed literature suggests a gap in research focusing on accessible design solutions. Developers should incorporate accessibility features such as audio prompts, visual icons, and simplified language into UI designs for illiterate users. Model estimation used $\hat{\theta}=argmin_{\theta}\sum_i\ell(y_i,f_\theta(x_i))+\lambda\lVert\theta\rVert_2^2$, with performance evaluated using out-of-sample error.