Seems that you aren't running the commands on the root directory.
1st and foremost you need to find the root directory where the PHP command will run.
It may vary according to your PHP configuration. For example, in my case, I am using Magento 2.35 and PHP 7.3. My commands are
- cd public_html, to enter in my current root directory
- /opt/alt/php73/usr/bin/php -d memory_limit=-1 bin/magento setup:upgrade
- /opt/alt/php73/usr/bin/php is for cli php 7.3
- memory_limit=-1 is for using all the memory available for the command
- bin/magento setup:upgrade, as you need
It is not easy to find the root and commands. If you are not familiar, you may ask your developer to find it or hire someone.
There are some people sharing means to get it on Google as well.