What type of issue is it?
Wrong documentation
What article/section is this about?
https://docs.umbraco.com/umbraco-forms/developer/field-types
Describe the issue
The article still refers to the umbracoforms.config file. I think this is now possible with the help of an app settings. See also the example below:
"Forms": {
"FieldTypes": {
"DatePicker": {
"DatePickerYearRange": 12
}
}
}