I have multiple domains on my hosting account and I have to make subfolders for each domain name. Is there a way to redirect it to the parent folder instead of root folder?
You can manage the setting from the control panel of your hosting company which will work only for the welcome page of your website.
But if any user will click on the homepage link, the folder name will be visible in the address bar. There is no other way to hide the folder name from the address bar. The only was is to move the files from sub folder to the root directory.
If you don't like it then change the name of your sub-folder from your domain.com to something else: like "onlinestore" or any other shortname which looks relevant.