Adhan is among the distinguishing signs of Islam. Such honour has been to those who carry out the duty of calling the Adhan that they will be among the distinguished people with high positions on the Day of Qiyamah.
Rasulullah (Sallallahu Alayhi Wasallam) is reported to have said, “Verily the muazzins will have the ‘longest necks’ on the Day of Qiyamah.” (Saheeh Muslim, Hadith 387)
Having long necks actually means that they will occupy positions of honour and distinction. Thus it is found that Hadhrat Bilal (radhiallahu anho) was held in high esteem among the Sahabah (radhiallahu ajmaeen) due to being the muazzin of Rasulullah (Sallallahu Alayhi Wasallam).
The following booklet deals on the etiquettes of the Adhan and the Iqamah and how to actually call them out: Adhan and Iqamah in Details