To delete stickers from the sticker library on your iPhone, open the Messages app, start a new message or enter a conversation, tap the “+” button, then tap Stickers. In the sticker drawer, tap and hold the sticker pack you want to delete, then select “Remove” or “Delete” from the menu. This removes the sticker pack from your library but doesn't delete the original app if it's tied to one—you'll need to delete that app separately if needed.