How to link a text field with a radio button - reactjs

Question

Before Clicking anything text field should be disable . when after the radio button selected my text field must be enable.

Answer 1

This is the working solution of your question.
class App extends React.Component {
state = {
isRadioSelected: true
};
changeHandler = () => {
this.setState({ isRadioSelected: false });
};
render() {
return (
<div className="App">
<h3>Input text is {this.state.isRadioSelected ? 'Disabled': 'Enabled'}</h3>
<input type="text" disabled={this.state.isRadioSelected} />
<br />
<label>Select Radio Button</label>
<input type="radio" onChange={this.changeHandler} />
</div>
);
}
}
ReactDOM.render(<App/>, document.getElementById('root'));
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/16.6.3/umd/react.production.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react-dom/16.6.3/umd/react-dom.production.min.js"></script>
<div id='root' />

Answer 2

Your description is pretty vague and you don't have any code samples, but here's likely what you want to do:
Make the radio button a controlled component, so that you can access it's value within React's state.
Tie the input's disabled attribute to the value of that state field.
It also seems like you want a checkbox, and not a radio button, since a radio button cannot be untoggled if there is only a single radio button.
This code will likely not work as-is (I haven't run it), but should provide a starting idea:
function Tester() {
const [radioValue, setRadioValue] = useState(false)
return (
<div>
<input type="radio" onClick={(e) => setRadioValue(e.target.value)} value={radioValue} />
<input type="text" placeholder="your input box" disabled={!radioValue} />
</div>
)
}