I've been learning Pega dev studio recently and the documentation for this section is a bit vague for me without an example on how it works. it can be with very simple values all I wish is to have the knowledge for future uses.
Like let's say if Age <=65 it transforms to elderly.
@SiulL168 Map Value allows you to map one or two inputs to a calculated result. You can learn more about them here. For example, you may want to convert longitude and latitude (inputs) to a city (output).
Given your example, I'd probably go for a decision table and two properties on the case level: Age (integer) and Designation (text). The latter would be a calculated field, tied to the result of a decision table - so as soon as the age changes, the designation will be changed along with it - declaratively.