SHAP uses matplotlib for visualization, so modifying its settings allows you to control the font size. To increase the font size of texts in SHAP plots, you can use 'matplotlib.rcParams'. The list of rcParams can be found here.
Here is an example:
import matplotlib.pyplot as pltplt.rcParams.update({'font.size': 16})
import matplotlib.pyplot as plt
plt.rcParams.update({'font.size': 16})
or
plt.rcParams['font.size'] = 16