Normally, if you use the field tool to add a field to the layout and include the field label at the same time, the label and field will remain correctly aligned with each other when the layout is opened in the iOS device. But details in how you set up your layout are important. Different design details such as line spacing and anchors can be part of the issue or not.
It's often very useful, time saving to host the file temporarily With FileMaker Pro and use WiFi to connect to it from the iOS device as a client as a fast way to check layout designs. You can then "tweak" layout design details on the computer and get nearly instantaneous results on the iOS gadget.