The formula to find the surface area of a rectangular prism is
[tex]\begin{gathered} \text{Surface area }=2(lh+wh+lw) \\ \text{ Where l is the length,} \\ \text{w is the width and} \\ h\text{ is the height of the rectangular prism} \end{gathered}[/tex]Graphically
So, in this case, you have
[tex]\begin{gathered} l=6\operatorname{cm} \\ w=3\operatorname{cm} \\ h=2\operatorname{cm} \\ \text{Surface area }=2(lh+wh+lw) \\ \text{Surface area }=2(6\operatorname{cm}\cdot2\operatorname{cm}+3\operatorname{cm}\cdot2\operatorname{cm}+6\operatorname{cm}\cdot3\operatorname{cm}) \\ \text{Surface area }=2(12\operatorname{cm}^2+6\operatorname{cm}^2+18\operatorname{cm}^2) \\ \text{Surface area }=2(36\operatorname{cm}^2) \\ \text{Surface area }=72\operatorname{cm}^2 \end{gathered}[/tex]Therefore, the surface area of the prism shown in the figure is 72 square centimeters.
And since it is about the area and you can see above, the surface area units are cm².