Outfit Inspiration

Indian Attire: Men are welcome to wear simple Kurta, or add a Sherwani, or Nehru Jacket. Women are welcome to wear a Lehenga, Saree (although we'd recommend trying one on first if you've never worn one before), or Kurta.
Indo-western: a mixture of western clothing trends with Indian traditional ethnic, hand-crafted embroidered, thread work.
Semi-Formal: Tuxedos are not required and guests are welcome to spice it up!
Online shopping destinations:
While not a comprehensive list, Indian and Indo-western attire can be purchased, spanning all price ranges, from sites such as: Lashkaraa, Pernia's Pop-Up, Aza Fashions, Kalki Fashion, Ogaan, Kynah, Panash India, and many more.
Brick and mortar retail: If located in Chicago, Devon Street is home to a plethora of reasonably priced Indian clothing shops. If your home base is NYC, Lexington Ave between 23rd and 34th, or Jackson Heights, provides several appropriate options.