Is there a way in ArcMap to force to populate fields that are declared "Allow Null Values to No" with values different from Empty when creating a new feature.
I changed in the feature description the Field Property: Allow Null Values to No, but when I create a new feature it populates this field with blank. Is there a way to check that the value entered is not blank?
Are you wanting to change the default value for a field? Does the Assign Default To Field (Data Management) tool not work for you?
Regarding your last question about finding a way to check whether the valued entered is blank or not, are you talking about doing this in real-time as a user inputs text or going back through the records to see which ones are blank and not blank?
Yes I would like to add some logic that requires editors to populate some fields before they save the record. I thought that Checking Allow Null Values in the feature class description will do that, but it doesn't.
I want to do it in real-time as a user inputs text.
Not allowing nulls is one way of forcing users to populate a field, but it sets the bar pretty low in terms of data quality expectations. If users are forced to enter something because nulls aren't allowed, and there are no restrictions on what can be entered, people will get creative on what they enter. In these situations, not allowing nulls is worse than allowing them because at least when nulls are allowed and a field is populated, the odds are better than not someone didn't just make up a value.
If you want to make users populate a field and you also want to increase the odds of having decent data, then it might make sense to look into Attribute Domains and Subtypes. If you want to allow non-null, free-form text than some level of programming will likely be needed to achieve what you are after.