Raffle Prompt
When you loot an item that is tradable, a prompt will appear asking if you want to trade the item. You can disable this feature via /raffle auto-detect off
Text-Based Raffles
If you're in a LFR or LFG PUG, you can raffle off items via chat. People who whisper you and can use the item will automatically be added to the raffle. If you raffle multiple items at the same time, they will need to whisper you with the item link.