Can I use Google Drive or Dropbox to share XML file and connect it to any HTML file at any place or web server , if yes , what are the steps ?

Yes you can.

Right click on the xml file on google drive and choose share then click on Get shareable link.

By using the shareable link, you will get public file link and you can use that link to connect wherever you want.

Yes you can do it easily for more details you can read my this article

http://www.nafisflahi.com///host-website-css-javascript-on-googledrive.html

Yes you can.

Right click on the xml file on google drive and choose share then click on Get shareable link.

For this purpose you have to work with google API to do that follow this link

https://developers.google.com/drive/web/quickstart/js