str.upper() str.lower() str.title(): Convert the cases of the font.

import pandas as pd 
my_dict={'NAME':['Ravi','Raju','Alex']}
df = pd.DataFrame(data=my_dict)
print(df.NAME.str.upper()) # convert Lower case to Upper case 

0    RAVI
1    RAJU
2    ALEX

lower() : Upper case to Lower case

import pandas as pd 
my_dict={'NAME':['Ravi','Raju','Alex']}
df = pd.DataFrame(data=my_dict)
print(df.NAME.str.lower())

0    ravi
1    raju
2    alex

title(): First char of each word to Upper case

import pandas as pd 
my_dict={'NAME':['ravi ron','raju geek','alex john']}
df = pd.DataFrame(data=my_dict)
print(df.NAME.str.title())

0     Ravi Ron
1    Raju Geek
2    Alex John

capitalize(): First Char to Upper case

import pandas as pd 
my_dict={'NAME':['ravi ron','raju geek','alex john']}
df = pd.DataFrame(data=my_dict)
print(df.NAME.str.capitalize())

0     Ravi ron
1    Raju geek
2    Alex john

swapcase(): Convert Lower to Uppper and Upper to Lower case

import pandas as pd 
my_dict={'NAME':['Ravi Ron','Raju Geek','Alex John']}
df = pd.DataFrame(data=my_dict)
print(df.NAME.str.swapcase())

0     rAVI rON
1    rAJU gEEK
2    aLEX jOHN