My solution with a second validation to check if the high number is higher than the low number

// Collect input from a user
const lowUserNumber = prompt('Please provide your lowest number.');
const highUserNumber = prompt('Please provide your highest number.');

// Convert the input to a number
const lowNumber = +lowUserNumber;
const highNumber = +highUserNumber;

console.log(lowNumber);
console.log(highNumber);

if(lowNumber && highNumber ){
  if ( (highNumber > lowNumber) ) {
    // Use Math.random() and the user's number to generate a random number
    const randomNumber = Math.floor( Math.random() * (highNumber - lowNumber + 1) ) + lowNumber;

 // Create a message displaying the random number
    document.querySelector('main').innerHTML = `${randomNumber} is a random number betwwn ${lowUserNumber} and ${highUserNumber}`;
  } else {
    document.querySelector('main').innerHTML = `The second number has to be higher than the first. Try again.`
  }

} else {
  document.querySelector('main').innerHTML = `You need to provide two numbers. Try again.`
}