import pandas as pd

# Creating a DataFrame
df = pd.DataFrame({'A': [1, 2, 3], 'B': [4, 5, 6]})

# Renaming all columns
df.set_axis(['NewA', 'NewB'], axis=1, inplace=True)

# Print data frame
print(df)

>>>

     NewA  NewB
0     1     4
1     2     5
2     3     6