set item in form

Isn't this the same as your previous question:
https://www.experts-exchange.com/questions/29008102/inserting-value-in-table-in-oracle-form.html

I remember other questions that were very similar about screen masking versus inserting the data.

no is not the same i just what to display value in this form in oracle form 6210-14-242-8258

If you want to physically update the data to add the dashes in the table on insert, then the form should just be able to display what it receives without any format masking.

If this is what you want to do, you should be able to apply the formatting inside the form and insert the data in the desired format.  I remember you asked a question on how to do that.  I just cannot find it.

I've not used forms for many years but are you wanting forms triggers or database level triggers?

If database level triggers:
If you cannot get forms to insert the data correctly, as a last resort you should be able to create a before insert trigger.  You might need an after insert trigger if forms interferes with the before trigger.

Can you show some sample values that get inserted and how you would like them to be after an update?

FM0999-99-999-9999

select regexp_replace(mycol,'([0-9]{4})([0-9]{2})([0-9]{3})([0-9]{4})','\1-\2-\3-\4')