I will describe the steps that need to be performed to transfer OpenCart to another hosting:
1) Copy the OpenCart files to the hosting, for example via FTP.
2) We make a database dump, for example through phpMyAdmin and upload it to the hosting in UTF-8 encoding.
3) On the new hosting, we’ll already edit two configuration files, config.php and /admin/config.php. In them, we will change the paths to the OpenCart files on the disk and the parameters for connecting to the database. The path to the files can be seen by creating the info.php file with the line below and opening it in the browser:
<?php phpinfo(); ?>
4) Lastly, set 0755 permissions on folders and files:
image/
image/cache/
image/data/
system/cache/
system/logs/
download/
config.php
admin/config.php
See also my article:
Installing OpenCart on Ubuntu Server