If you have your website's backup and want to upload it to your new account at Hostinger, you can accomplish this task in three different ways:
1. Upload backup with Import Website feature:
It will immediately unpack your tar/tar.gz/zip archive to public_html. The best choice if you have 1 archive with a size of less than 256 MB.
2. Upload backup with File Manager (Beta) feature:
The upload limit is 100GB.
3. Upload backup with FTP client:
There is no upload limit for FTP.