You can use a pressure-sensitive tablet, for example, Wacom or MS Surface, with the Blue Pencil tool. For best results, make sure to have the latest drivers installed.
When you use a tablet with Blue Pencil, you can
To use a tablet pressure settings with Blue Pencil
or the Brush
tool in the
Blue Pencil toolbar and activate the
Enable Tablet Pressure for Opacity and
Enable Tablet Pressure for Size options.

Pencil tablet pressure settings
You can switch the Tablet API in the Tablet API section of the Interface Preferences. (See ) See also Tablet Setup.
To use the falloff curve to create a custom Blue Pencil stroke
icon in the Last Used tool area of the
Tool Box, or click the Tool settings button
in the upper right corner of Maya to open the
Blue Pencil Tool Settings.
, Brush
, or Eraser
icons in the
Drawing area to expand the settings for the tool.
If either of these events occur, set the Tablet API setting in the Interface Preferences to Wintab.