Setting up Axes
Define interpolation axes in File → Font Info… → Font → Axes. Click the plus button next to the Axes heading to add a new axis. An axis has a name, a four-character tag, and a hidden-checkbox.
Click the disclosure button to pick one of the predefined axes.
Choosing a predefined axis also sets its four-character tag field with the respective value.
The predefined axes are a combination of the registered OpenType design-
Check the Hidden checkbox to hide an axis in user interfaces. If set, this signals to applications using the font that they should not display controls (such as a slider) for this axis. Hide axes if they are applicable only in specialized software. Applications may or may not respect this option. In most cases, this checkbox should be left unchecked.