How is wedding car decoration done in islam?

All perfect praise be to Allah, The Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad, sallallahu ‘alayhi wa sallam, is His slave and Messenger.

We do not see any harm in decorating the car of the bride and groom as long as it does not amount to extravagance and excess. The basic principle in such matters is that they are lawful. However, the Muslim should beware of other prohibitions that may occur during weddings, such as mixing between men and women and exposing the bride's beauty and adornments before non-Mahram (marriageable) men. Also, the bride should wear a decent dress and avoid imitating the disbelievers in their clothing.

The Standing Committee for Scholarly Research and Fatwa was asked, “Does wearing a white dress on the wedding day and relevant ornaments have an Islamic origin? If it has an Islamic origin, is it permissible for the bride to uncover her face on her wedding night, given that there are non-Mahram men, on the way to her husband's house?”

The answer reads, “It is permissible for the woman to wear a wedding dress or any kind of clothes that women wear on the wedding day provided that it covers her body and does not entail imitation of men or disbelieving women. It is not permissible for the woman to uncover her face in front of non-Mahram men on her wedding night or on any other night.”

Allah knows best.