Forms and Controlled Inputs

A controlled input has its value driven by React state.

The user types. onChange updates state. The input shows that state. React is the single source of truth.

One text field

Why value and onChange together

If you set value and skip onChange, the field freezes. React keeps showing the old string.

If you skip value, the input is uncontrolled. The DOM owns the text. That is harder to reset and validate.

Checkbox

Checkboxes use checked and event.target.checked, not value.

Select

Several fields

You can use one state object, or one useState per field. Both are fine.

Tip: Always preventDefault on submit. Then read state. That is a React form.