Iodised salt, seafood, dairy and eggs can contribute iodine. At the shop, look for the word iodised on the salt you buy. Colour and grain size cannot tell you if iodine was added.
Use the back of the pack
If you use pink salt, sendha namak or another specialty salt, check the actual label. If iodine is one reason you are choosing a salt, compare labelled packs while keeping the amount of salt you normally use.
Compare fortified salt labels
Double fortified salt lists iron as well as iodine. Look at the printed nutrient information so you know which kind is in your cupboard. Read a nutrition label · FSSAI fortification guide · NIH iodine fact sheet
High-fibre Indian pantry foods and where to use them
Take one minute at the salt shelf
Turn over your regular salt and one other pack. Look for iodisation in the description or ingredients. If you find it on both, keep comparing based on the kind you need for cooking and the amount you normally use. If you buy double fortified salt, check the separate iodine and iron information. At home, keep a photo of the label if you transfer the salt to an unmarked jar.