To change the field size of a text or number field in Microsoft Access, follow these steps:
- Open your Access database.
- Locate the table where you want to change the field size.
- Right-click on the table name in the 'Navigation Pane' and select 'Design View'.
- In the 'Design View', find the field whose size you want to change.
- Look at the bottom of the window in the 'Field Properties' section. Change the value of the field size.
- Enter a number between 1 and 255 to define the maximum number of characters allowed.
- After modifying the field size, click the 'Save' button to save the table.