Digital affordances exist on the touchscreen, but the affordance of virtual buttons on smartphones is unknown. Therefore, this study investigated the on-screen affordances by examining whether the visual properties of virtual keyboard buttons could afford possible clicking actions and affect the entry performance. This study employed a three-way within-subject design: 2 (Symbol Position: standard mode vs. corrective mode) × 2 (Button Border: bordered button vs. borderless button) × 26 (Button Position: 26 positions). In the serial tapping task, 30 university students tapped virtual keyboard buttons with four button types. The results confirmed that the symbol-position and button-border variables influenced clicking actions. When employing offset-correcting symbols, the entry accuracy of virtual keyboard buttons increased without the speed-accuracy tradeoff. Additionally, button borders improved the perceived usability of virtual keyboard buttons despite failing to enhance the entry accuracy and speed. However, the button position moderated the effects of the symbol-position and button-border variables.