It's not absolutely necessary to make any changes at all. An iOS device can access the same exact file and interact with the same exact layouts.
But it's usually a good idea to add layouts customized for the type of iOS devices that will be accessing the file. This involves redesigning layouts to work better with the smaller screens and touch interaction--your finger is a "blunter" less precise pointing tool than a mouse.
A start up script can use Get ( Device ) to identify the device and select the appropriate set of layouts to make accessible to that device.
Here's a "blog type" thread where I documented my early adventures customizing a solution for use with an iPhone 4. The techniques discussed are still pretty applicable to the latest devices: An Old Dog learns some new tricks...