Answers for "change font size in plt"

matplotlib plot title font size

from matplotlib import pyplot as plt    

fig = plt.figure()
plt.plot(data)
fig.suptitle('test title', fontsize=20)
plt.xlabel('xlabel', fontsize=18)
plt.ylabel('ylabel', fontsize=16)
fig.savefig('test.jpg')

matplotlib change text size

import matplotlib.pyplot as plt
plt.rcParams.update({'font.size': 22})

change font size in plt

font = {'family' : 'normal',
        'weight' : 'bold',
        'size'   : 22}

matplotlib.rc('font', **font)