useEffect is a React hook used to handle states within a component.

Example:

 const [name, setName] = useState('');

This would declare a variable called name which depending on the component's lifecycle can have multiple states.

If we want to make an input that receives data from the user, it could be as follows:

 const myComponent = () => { const [userName, setUsername] = useState(null) const [password, setPassword] = useState(null) return ( <> <input type="text" placeholder="Enter userName..." onChange={e => setUsername(e.target.value)} value={userName || ''}/> <input type="password" placeholder="Enter Password..." onChange={e => setPassword(e.target.value)} value={password || ''}/> </> ) }