The money you get in exchange for the labour/ services that you provide at the end of the day/month is your income.

Example: For example Radha works at a tailor shop. She gets 100 rupees for each blouse she stitches. Let us assume she stitches 50 blouses in a month then her monthly income will be 5000 rupees. Or any other place where she is earning money will be considered her income like, rent from a room, money after selling crops in the village etc.