Is There Adhan or Iqamah for Nafl Prayers?
Question

In the case of voluntary (nafl) prayers such as Salat al-Duha or Salat al-Layl (qiyam al-layl), is there any adhan and iqamah, or not?
Praise be to Allah.No, there is no adhan or iqamah for nafl prayer s. If you do wudu and then pray as much as you like, such as Duha prayer, or after Zuhr, or in the last part of the night, or at any other time, apart from the times when prayer is not allowed , these prayers are to be done without adhan or iqamah.
It was not narrated that when the Messenger of Allah (peace and blessings of Allah be upon him) stood up to pray [any optional prayer], he gave the adhan or the iqamah . 
The adhan and iqamah are only for the obligatory prayers . But for Tarawih, Witr and other optional prayers, there is no adhan or iqamah, as the scholars have stated, and as is the Sunnah of the Messenger of Allah (peace and blessings of Allah be upon him) and the Rightly Guided Caliphs.
And Allah knows best.