Edit in JSFiddle

/* 
	The addressAutocomplete takes as parameters:
  - a container element (div)
  - callback to notify about address selection
*/
function addressAutocomplete(containerElement, callback) {
  // create input element
  var inputElement = document.createElement("input");
  inputElement.setAttribute("type", "text");
  inputElement.setAttribute("placeholder", "Enter an address here");
  containerElement.appendChild(inputElement);


  /* Current autocomplete items data (GeoJSON.Feature) */
  var currentItems;

  /* Active request promise reject function. To be able to cancel the promise when a new request comes */
  var currentPromiseReject;

  /* Execute a function when someone writes in the text field: */
  inputElement.addEventListener("input", function(e) {
    var currentValue = this.value;

    /* Close any already open dropdown list */
    closeDropDownList();

    // Cancel previous request promise
    if (currentPromiseReject) {
      currentPromiseReject({
        canceled: true
      });
    }

    /* Create a new promise and send geocoding request */
    var promise = new Promise((resolve, reject) => {
      currentPromiseReject = reject;

      var apiKey = "47f523a46b944b47862e39509a7833a9";
      var url = `https://api.geoapify.com/v1/geocode/autocomplete?text=${encodeURIComponent(currentValue)}&limit=5&apiKey=${apiKey}`;

      fetch(url)
        .then(response => {
          // check if the call was successful
          if (response.ok) {
            response.json().then(data => resolve(data));
          } else {
            response.json().then(data => reject(data));
          }
        });
    });

    promise.then((data) => {
      currentItems = data.features;

      /*create a DIV element that will contain the items (values):*/
      var autocompleteItemsElement = document.createElement("div");
      autocompleteItemsElement.setAttribute("class", "autocomplete-items");
      containerElement.appendChild(autocompleteItemsElement);

      /* For each item in the results */
      data.features.forEach((feature, index) => {
        /* Create a DIV element for each element: */
        var itemElement = document.createElement("DIV");
        /* Set formatted address as item value */
        itemElement.innerHTML = feature.properties.formatted;

        /* Set the value for the autocomplete text field and notify: */
        itemElement.addEventListener("click", function(e) {
          inputElement.value = currentItems[index].properties.formatted;

          callback(currentItems[index]);

          /* Close the list of autocompleted values: */
          closeDropDownList();
        });

        autocompleteItemsElement.appendChild(itemElement);
      });
    }, (err) => {
      if (!err.canceled) {
        console.log(err);
      }
    });
  });


  function closeDropDownList() {
    var autocompleteItemsElement = containerElement.querySelector(".autocomplete-items");
    if (autocompleteItemsElement) {
      containerElement.removeChild(autocompleteItemsElement);
    }
  }

}

addressAutocomplete(document.getElementById("autocomplete-container"), (data) => {
  console.log("Selected option: ");
  console.log(data);
});

<div class="autocomplete-container" id="autocomplete-container"></div>

body {
  font: 16px;
  background: #f3f5f6;
}

.autocomplete-container {
  /*the container must be positioned relative:*/
  position: relative;
}

.autocomplete-container input {
  width: calc(100% - 43px);
  outline: none;
  
  border: 1px solid rgba(0, 0, 0, 0.2);
  padding: 10px;
  padding-right: 31px;
  font-size: 16px;
}

.autocomplete-items {
  position: absolute;
  border: 1px solid rgba(0, 0, 0, 0.1);
  box-shadow: 0px 2px 10px 2px rgba(0, 0, 0, 0.1);
  border-top: none;
  z-index: 99;
  /*position the autocomplete items to be the same width as the container:*/
  top: calc(100% + 2px);
  left: 0;
  right: 0;
}

.autocomplete-items div {
  padding: 10px;
  cursor: pointer;
  background-color: #fff;
}

.autocomplete-items div:hover {
  /*when hovering an item:*/
  background-color: rgba(0, 0, 0, 0.1);
}