The Iron 883 is designed to seat one. It doesn’t come stock with a passenger seat or pegs for a second person to put their feet on. It has an 86″ length with a forward-heavy design. This makes it an awkward bike for taking a passenger.
That said, it is technically possible. You can always customize your motorcycle to make it fit two. There are aftermarket options available for adding a passenger seat and pegs. The 883cc Evolution engine is also strong enough to bear a reasonable amount of weight and still get decent acceleration. Even so, the experience might be less than ideal.
One Reddit user started a thread asking riders who had modified their Iron 883 motorcycles into two-seaters how comfortable the experience was. Several riders reported that they had converted their bikes, and the overall consensus was that the experience was underwhelming and a little less stable than you would like. One reported that you probably need to get new shocks because “the stock shorties are kidney beaters.” But even then, his passenger reported that she felt much safer and more comfortable on a bigger bike. Most of these Redditers also mentioned that the Iron 883 felt squirrely and struggled to get up to higher speeds when riding with a second person. So while it is possible, you’d probably be better off getting a larger Harley if you want a bike that’s made to carry more than one person.