Join two columns:

import pandas as pd

df = pd.DataFrame(columns=['Name', 'Age'])

df.loc[1, 'Name'] = 'Rocky'
df.loc[1, 'Age'] = 21

df.loc[2, 'Name'] = 'Sunny'
df.loc[2, 'Age'] = 22

df.loc[3, 'Name'] = 'Mark'
df.loc[3, 'Age'] = 25

df.loc[4, 'Name'] = 'Taylor'
df.loc[4, 'Age'] = 28

print('\n------------ BEFORE ----------------\n')
print(df)

df['Employee'] = df['Name'].map(str) + ' - ' + df['Age'].map(str)
df = df.reindex(['Employee'], axis=1)

print('\n------------ AFTER ----------------\n')
print(df)

C:\pandas>python example41.py
 
------------ BEFORE ----------------
 
     Name Age
1   Rocky  21
2   Sunny  22
3    Mark  25
4  Taylor  28
 
------------ AFTER ----------------
 
      Employee
1   Rocky - 21
2   Sunny - 22
3    Mark - 25
4  Taylor - 28
 
C:\pandas>