How to install on shared hosting without Composer available?

You can execute composer on your laptop then FTP the resulting codebase.

I do not think there is another possible way.

I would recommend that you find a shared hosting provider with SSH access, more and more places now offer it:

https://presearch.com/search?q=shared+hosting+providers+SSH+access

SSH or FTP, the answer is the same: build the codebase somewhere else then upload it.

Sure. It's possible with FTP, but I certainly won't recommend it, and the reason I suggest finding hosting with SSH.

I mainly using a vps which has no problem, but one of the web will be on another share hosting which won't works. I normally build the site online directly, everytime module upgrade just one click through the UI, if build locally then upload, will takes 3x more times..

If Composer cannot be executed on the hosting platform you will have to build the codebase some other place then upload it.

Two strategic initiatives → , Automatic Updates and Project Browser, are targeted at this use-case. But as far as I know at the time I write this, those are not yet completed.

Community members identified shared hosting as a difficult use-case for Composer-based codebases before Drupal 8 launched, in 🌱 Proposed workflow for Composer + module download on cheap hosting / FTP Closed: duplicate . Even that issue says:

In Drupal 8, if you have modules that introduce composer dependencies in addition to those in core, you need to run composer update with the CLI. This is going to be difficult for the cheap hosting + FTP scenario...

One solution is to run Composer locally and copy the changes to the server with FTP. But some people might not even be comfortable with that.

one of my site is in Drupal9, I have about 40 modules installed through ftp upload, except the commerce module, none of them has any dependences that need to be installed through composer , so I am just curious why force composer for the project when most of the modules don't need it.

As I mentioned not requiring Composer is a strategic initiative.