Mediation in SmartPLS
Mediation occurs when a third mediator variable intervenes between two other related constructs. More precisely, a change in the exogenous construct causes a change in the mediator variable, which, in turn, results in a change in the endogenous construct in the PLS path model. Thereby, a mediator variable governs the nature (i.e., the underlying mechanism or process) of the relationship between two constructs.
Analyzing the strength of the mediator variable’s relationships with the other constructs allows substantiating the mechanisms that underlie the causeeffect relationship between an exogenous construct and an endogenous construct. In the simplest form, the analysis considers only one mediator variable, but the path model can include a multitude of mediator variables simultaneously.
Hair et al. (2017) describe the systematic mediator analysis process in PLSSEM in more detail; also see Nitzl et al. (2017)
SmartPLS supports to model and analyze mediators.
The SmartPLS results of the PLS algorithm and the bootstrap procedure include the direct, the (total and specific) indirect effect, and the total effect. These results permit conducting a mediator analysis (e.g., as suggested by Hair et al. 2017).
References

Hair, J. F., Hult, G. T. M., Ringle, C. M., and Sarstedt, M. (2017). A Primer on Partial Least Squares Structural Equation Modeling (PLSSEM), 2nd Ed., Sage: Thousand Oaks.
 Nitzl, C., Roldán, J. L., and Cepeda Carrión, G. (2016), Mediation Analysis in Partial Least Squares Path Modeling: Helping Researchers Discuss More Sophisticated Models, Industrial Management & Data Systems, 119 (9), 18491864.