Dynamic behavior of forms can be achieved by utilizing Dynamic Logic feature. Dynamic Logic parameters are available for every fields. Parameters are available in Entity Manager when you edit or create a field.
Dynamic Logic allows to define conditions making certain fields visible, required or read-only. Conditions will be checked automatically when data in the form is changed.
For Enum, Array, Multi-Enum, Checklist fields it's possible to define different sets of options that will be available for the field depending on which condition is met. Note, that an order of option lists is taken into account.
Conditions are configured through user interface, no coding required.
In Layout Manager you can specify conditions making a specific panel visible. Available since the version 5.2.6.