In this paper, we consider the multiple-input-multiple-output (MIMO) system employing spatial modulation (SM)-based transmission in Rayleigh fading channels with known slow-varying large-scale fading loss and channel correlations. Observing that the system performance is affected by transmission mechanisms and configurations, we propose a framework enabling the selection of the transmission mode for the optimal spectral efficiency (SE) or energy efficiency (EE) while conforming to transmission and error rate requirements with low complexity. In the framework, a closed-form error rate approximation is proposed. It renders the formulated SE-and EE-based selection problems solvable via naive exhaustive search method. Moreover, we propose to reduce the complexity via using lookup tables. Computer simulations are provided to evaluate the framework.