One area that can be particularly difficult is distinguishing letters, so when someone spells their name or email over the phone it can be hard to be sure if you hear it correctly. Even native English speakers will use the technique of saying "B as in boy" (for example) to clarify which letters they are saying. But if you have a long name or email address, you may not want to spell out each letter this way as it will take a long time.
Use the video below to learn more about which letters can be confused and what you can say to make it clear which letter you are using.