A default value will be entered into the table unless a user specifically changes it.
If some of your data is predictable or probable, you can set default values for those controls. People won't need to enter data there unless they want it to differ from the default values.
To set a simple default value such as text, you would select a control in Design view, click the Properties button , then click the Data tab. You would enter the value in the Default Value property box. New records would open with that value in the control.
A default value can involve a calculation. For example, if most customers use second-day shipping, an expression could add two days to the current date as the default date of arrival.