st = "hello world"
st = st.encode('utf-8')
# binary value for letter 'h'
bin(st[0]) -> '0b1101000'
# binary value for letter 'e'
bin(st[1]) -> '0b1100101'

0  1
0  0
0  1
1  0
0  0
1  1
1  1
b  b
0  0