A desktop publishing application from Microsoft that focuses on page layout and graphic design.
Sorry, I was a bit too concise and forgot to tell you to use FTP to upload your web files and folders.
You seem to be using a file manager function built-in to your web control panel. That only allows you to move individual files. I would suggest that you download and install the free FTP tool FileZilla and use it to upload your files...and folders. https://filezilla-project.org/download.php
I would guess that if you look in the support section of your web host you will get specific instructions on how to use FileZilla to upload your web files under FTP instructions. If not the excellent, general instructions at the filezilla site will suffice...it is easy to use...especially after you figure it out once.
The alternative is messy and I am hesitant to suggest it. Right now the default is set in Publisher to organize your supporting files in the index_files folder. You can change that default.
Open Publisher > go to File > Options > Advanced > scroll down until you find the Web Options button > under Savings uncheck 'Organize supporting files in a folder'. Now when you export your web files Publisher will produce all the web files loose. Be careful to create a folder on your local computer where you can easily find it, and export/direct all those files to that folder. Now the index.html file will be mixed in, loose with the dozens, perhaps hundreds of supporting graphic and web files that used to be neatly contained in the index_files folder. I don't recommend this approach because it becomes exponentially more difficult to manage sometimes hundreds of files if you have a multipage website. Each time you edit your website you will have to upload the changes. It is much harder when you have all those loose files on your server.
In other words, take 10 minutes to learn how to FTP your files to your webhost and you will avoid making mistakes and a lot of hassle.
DavidF