Code: HelloWorld.html

<template> 
   <lightning-card title="HelloWorld" icon-name="custom:custom14">
      <div class="slds-m-around_medium">
          <p>Hello, {greeting}!</p>
              <lightning-input label="Name" value={greeting} 
                 onchange={changeHandler}>
            </lightning-input>
      </div>
   </lightning-card>
</template>