When working with Business Process Flows most of the times we get a requirement to show/hide a field based on business conditions. We used to write a Code for it on the Stage Change and Stage Select Events.
In CRM 2016, these kind of things can be achieved using combination of Business Process Flow and Business Rule.
Here are the steps for it.
1) Open Entity Customizations and Business Rule. I have taken Opportunity as an example.
2) Create a New Business Rule as shown in the below image. I have an example to hide Proposed Solution field when Active Stage is Develop and Customer Need field contains data.
We can also write Business Rule on the Stage Change. Here is the sample for it.
In the same way, you can write business rule for setting Required Level/Visibility/Populate some value etc..
Hope this helps.