Recommendation: "Add" button on dropdowns

I have several forms with drop down lists and would like the user to be able to add a new record to the dropdown list without having to go out of the form. Looking for suggestions on how to implement this. Should this be done in the "Add" form or can it be added to the Blazor component?

There is no such functionality built-in. You can use a button to add data to the collection bound to the DropDown. update the form by adding an "Add" button next to the drop down.