Betting using the Racing Post app doesn't limit you to only placing single or multiple bets, and there are other additional markets you can choose from.
If you think you can predict the finishing order of the top two places (forecast), or the first three places (tricast) you can place these bet types with any of the four integrated bookmakers on the app.
You can place this bet type by adding multiple selections to the Bet Slip from the same race. An option in the bet slip for Forecast/Tricast will be displayed. The drop-down menu allows you to place the bet straight or reversed (2 bets) and the amount you wish to stake.