A good option for a tool that can quickly mock up something for clients to see, and could also be used to publish the iOS and Android apps, is Adobe Animate:
Buy Adobe Animate | Flash and 2D animation software
One of XD's main benefits is the time that it can save during the client approval stage. With other tools you would need to do a certain amount of coding to get a good enough interactive demo, and often you might put a lot of effort into the approach that you hope will be approved, so that you can then continue to use that particular code in the real application. Things don't always work out that way, and you sometimes have to start from scratch, and go through another round of approval. With XD your developers start their work by being able to look at an already approved working prototype, so even if they cannot reuse any element of the prototype, it still saved them a lot of time.