Theory:

A homophone means two or more words that have the same pronunciation but different meanings, origins or spellings. "Homo" means "same" and "phones" mean "sound". Hence homophones are words that produce the same sound when pronounced.
Example:
1. know - no
2. bear - bare
3. heal - heel
4. made - maid
5. pair - pear
It is important to understand and practise homophones because the incorrect usage of such words can change the meaning of the whole sentence.
Example:
1. break - brake:
  
break coffee.jpg brake.jpg
 
Break - a pause in work, for coffee etc; Brake - a device for slowing down a vehicle.
  
We had a tea break for ten minutes.
I did not take my car because the brakes had failed.
 
2. heal - heel:
  
heal.jpg feet-2813132_1920.jpg
 
Heal - Recover to being healthy; Heel - the back part of the human foot.
 
The injury will take some time to heal.
I had injured my heel during the training.
 
3. pair - pear:
  
pair.jpgpear.jpg
  
Pair: A set of two things regarded as one; Pear - a fruit.
  
I had a pair of shoes in my bag.
It was a pear-shaped bag that I lost.
Important!
A list of commonly used homophones can be found here.