Punjabi suits are not required for the wedding ceremony; however if you choose to purchase a suit, I have provided some links where you can order online. Etsy has lots of great options, and that would be the best place to purchase. If you choose not to wear a Punjabi suit, your dress attire should be modest. Links: https://www.etsy.com/search?q=punjabi+patiala+traditional+suit&ref=search_bar https://www.lashkaraa.com/collections/punjabi-suits https://www.utsavfashion.com/salwar/punjabi-suits https://www.panashindia.com/salwar/punjabi-suits
Men typically wear a suit with a turban. Historically, the turban was a symbol of high social status and royalty, it was adopted by Sikhs to remind humans that all are sovereign, royal, and ultimately equal. It is also used symbolically to remind us to protect our "crown" as it is the way that we communicate with God. Out of respect for the Sikh faith, your head must be covered in the presence of their Holy Book, the Granth Sahib. The Granth Sahib will be present only during the Blissful Ceremony.
The Blissful Ceremony is the name of the traditional Sikh wedding ceremony. Upon entering the ceremony room, everyone will remove their shoes. There will be no chairs, everyone will sit on the floor. The ceremony will last 30-45 minutes. It is traditional to sit on the floor when before the Granth Sahib (the Sikh Holy Book) as a reminder that before God, everyone is equal.