The structural pattern for changing voice in simple present tense is – 

Active VoicePassive Voice
SUBJECT + VERB(S/ES/IES) + OBJECT OBJECT + AM/IS/ARE + VERB(PAST PARTICIPLE) + BY/TO/WITH + SUBJECT 

Examples

Active VoicePassive Voice
He plays hockey.Hockey is played by him.
Mother gives me money for my study.Money is given to me for my study by mother
I do my homework every day.My homework is done every day by me.
Lata sings classical songs.Classical songs are sung by Lata.
The farmers produce food for everyone.Food for everyone is produced by the farmers.
I read a poetry every day.A poetry is read every day by me.
The magician knows wonderful tricks.Wonderful tricks are known by the magician.
The trees give us oxygen.Oxygen is given to us by the trees.
The bees collect honey from the flowers.Honey is collected from the flowers by the bees.
The tiger hunts deer.Deer is hunted by the tiger.