If you need to spell you name over the phone it is important to avoid misunderstandings.
The best way is to using the aviation alphabet. This is commonly used in the travel and aviation industry and is known well.
A- Alpha H- Hotel O- Oscar U- Uniform
B- Bravo I- India P- Papa V- Victor
C- Charlie J- Juliet Q- Quebec W- Whiskey
D- Delta K- Kilo R- Romeo X- X-Ray
E- Echo L- Lima S- Sierra Y- Yankee
F- Foxtrot M- Mike T- Tango Z- Zulu
G- Golf N-November