As far as Islam is concerned, there is nothing un-Islamic about couples sitting on a platform during a wedding ceremony as long as the Islamic rules of modesty and morals are complied with. The reason for this is that this practice is not a religious requirement but merely a custom, and the original rule regarding customs is that everything is permissible unless it is clearly prohibited.
Sheikh Muhammed Nur Abdullah, President of the ISNA (Islamic Society of North America) and member of the Fiqh Council of North America, states: “The marriage ceremony can take place either in a masjid, with people sitting on the floor, or in any hall where the couple may be sitting on a platform, like a stage, so that they can be seen by people. The requirements are that the ceremony should conform to the Islamic rules and conditions, and it is important that men and women be separated, e.g., men in the front and women in the back, or they can be in different sides of the place.
The basic requirements for marriage are: offer, acceptance, mahr, at least two male, adult, Muslims as witnesses, and that the marriage be made public. If this is complied with, any addition should be acceptable as long as long there are no statements which include shirk.
The way in which a marriage ceremony takes place is a part of one’s culture, and the Prophet (peace and blessings be upon him) adopted different cultures when he migrated from Makkah to Madinah, like when he asked `A’ishah saying, “Have you seen anything wrong in the couple?” and he told her that the Ansar are people who loved singing and that was their culture. The way people sit and act in a marriage ceremony is also based on culture, and the important thing is that culture should never contradict any Islamic teaching”