1. Select Edit Mode to open your drawing;
2. Tap Settings in the upper right corner;
3. Find Dimension settings in the Settings page;
4.Tap Dimension settings, the Arrow and Suffix options would pop up;
5. Tap Arrow to set the dimension style, tap Suffix to enter the suffix required, and then tap OK to complete;
6. After completing the settings of dimension, the new dimension will apply the style we just set, as shown in the following picture: