When we celebrate Milad, we gather, in order to send salutations (Esal-e-Swaab) to the Prophet Muhammad [May ALLAH Bless Him and Grant Him Peace],
give charity to the poor (Sadaqah Khairat) and remember wilaadah(Birth)
and virtues of the Prophet Muhammad [May ALLAH Bless Him and Grant Him Peace]. The Ahl as-Sunnah does not say that one must celebrate “Milad” only on 12 Rabee’-ul-Awwal,
in fact it can be celebrated at anytime of the year. Generally Milad-un-Nabi is celebrated, on the 12th of Rabee’ul-Awwal, by Muslims all over the world. In every Muslim country, there is a public holiday for “Milaad-un-Nabee”, except one country, but even in that country, the people celebrate “Milaad” individually.