When you set a default value for a field, the field will automatically default to that value when you are creating new records or when you are editing existing records and the field value is empty.
In cases where you need to “clear” fields with defaults, you can use a placeholder text or a special item in a choice field to indicate a “no value”. For choice fields, the default value can be selected from the choice options you have entered. For the other field types you can manually enter the value you wish.
Default Value is available on the following Field types: Text, Numeric, Yes/No, Date, Time, and Choice fields (Single choice, Multiple choice)