You can use the following basic syntax to adjust axis label positions in Matplotlib:

#adjust y-axis label position
ax.yaxis.set_label_coords(-.1, .5)

#adjust x-axis label position 
ax.xaxis.set_label_coords(.5, -.1)

The following examples show how to use this syntax in practice.

Example 1: Adjust X-Axis Label Position

The following code shows how to create a plot in Matplotlib and adjust the location of the x-axis label position only:

import matplotlib.pyplotas plt

#define data
x = [1, 2, 3, 4, 5, 6]
y = [4, 5, 8, 14, 24, 19]

#create scatterplot
fig, ax = plt.subplots()
ax.scatter(x, y)

#add axis labels
ax.set_ylabel('Y-Axis Label')
ax.set_xlabel('X-Axis Label')

#adjust position of x-axis label
ax.xaxis.set_label_coords(.9, -.1)

Note that the axis coordinate system uses (0, 0) to represent the bottom left corner of the plot, (0.5, 0.5) to represent the center, and (1, 1) to represent the top right corner.

Example 2: Adjust Y-Axis Label Position

The following code shows how to create a plot in Matplotlib and adjust the location of the y-axis label position only:

import matplotlib.pyplotas plt

#define data
x = [1, 2, 3, 4, 5, 6]
y = [4, 5, 8, 14, 24, 19]

#create scatterplot
fig, ax = plt.subplots()
ax.scatter(x, y)

#add axis labels
ax.set_ylabel('Y-Axis Label')
ax.set_xlabel('X-Axis Label')

#adjust position of x-axis label
ax.yaxis.set_label_coords(-.1, .1)

Example 3: Adjust Both Axis Label Positions

The following code shows how to create a plot in Matplotlib and adjust the location of both axis label positions:

import matplotlib.pyplotas plt

#define data
x = [1, 2, 3, 4, 5, 6]
y = [4, 5, 8, 14, 24, 19]

#create scatterplot
fig, ax = plt.subplots()
ax.scatter(x, y)

#add axis labels
ax.set_ylabel('Y-Axis Label')
ax.set_xlabel('X-Axis Label')

#adjust position of both axis labels
ax.yaxis.set_label_coords(-.1, .1)
ax.xaxis.set_label_coords(.9, -.1)