f-strings is a short for "formatted strings", provides a convenient way to embed expressions inside string literals. This supports more formatting options than the old str.format() method supports.
Few examples;
String operation
>>> name = 'Arunkumar'
>>> f'My name is {name.upper()}'
'My name is ARUNKUMAR'
Float formatting
>>> import math
>>> f'math.pi:.5f'
'3.14159'
Datetime formatting
this_day = datetime.now()
f'Yesteday was {this_day + datetime.timedelta(days=-1):%A} and tommorow is {this_day + datetime.timedelta(days=-1):%A}'
'Yesterday was Wednesday and tommorow is Friday'
f-string token looks like;
f ' <text> { <expression> <optional !s, !r, or !a> <optional : format specifier> } <text> ... '
Starting from 3.8 f-string supports "=" symbol for documenting expressions
>>> sum = 5 + 6
>>> f'{sum=}'
'sum=11'
Hope this helps!