Lend it, get paid, get it back
Watch what comes back.
Instead of locking ₹1,00,000 in a drawer, you lend it to a bank for three years. In return the bank pays you 8% a year .
Each year ₹8,000 comes to you. At the end, the ₹1,00,000 comes back too. That is fixed income : you lend money, you're paid a fixed interest, and you get your money back on a set date.