How to show legend elements horizontally in Matplotlib?

To show legend elements horizontally, we can take the following steps

Set the figure size and adjust the padding between and around the subplots.
Using plot() method, plot lines with the labels line1, line2 and line3.
Place a legend on the figure using legend() method, with number of labels for ncol value in the argument.
To display the figure, use show() method.

Example

from matplotlib import pyplot as plt

plt.rcParams["figure.figsize"] = [7.50, 3.50]
plt.rcParams["figure.autolayout"] = True

line1, = plt.plot([1, 2, 3], label="line1")
line2, = plt.plot([3, 2, 1], label="line2")
line3, = plt.plot([2, 3, 1], label="line3")
plt.legend(ncol=3, loc="upper right")
plt.show()