script.js

const input=document.querySelector('input');
const btn=document.querySelector('.addTask > button');
btn.addEventListener('click',addList);
input.addEventListener('keyup',(e)=>{
    (e.keyCode== 13 ? addList(e):null);
}); 
function addList(e){
    const notCompleted=document.querySelector('.notCompleted');
    const Completed=document.querySelector('.Completed');
    const newLi=document.createElement('li');
    const checkBtn=document.createElement('button');
    const delBtn=document.createElement('button');
    checkBtn.innerHTML='<i class="fa fa-check"></i>';
    delBtn.innerHTML='<i class="fa fa-trash"></i>';

    if(input.value!==''){
        newLi.textContent=input.value;
        input.value='';
        notCompleted.appendChild(newLi);
        newLi.appendChild(checkBtn);
        newLi.appendChild(delBtn);
    }
     checkBtn.addEventListener('click',function(){
        const parent=this.parentNode;
        parent.remove();
        Completed.appendChild(parent);
        checkBtn.style.display='none';
     });
     delBtn.addEventListener('click',function(){
        const parent=this.parentNode;
        parent.remove();
        });
}