iphoto is no longer supported. how do i upgrade?

Here's some info on how you can upgrade from iPhoto to Photos

Updating from iPhoto to Photos for macOS – Apple Support

iPhoto was discontinued 5 years ago. It is no longer developed or sold. It was replaced by the more powerful (and free) Photos.app that comes with the OS. You can migrate to that app very simply:

Hold down the option (or alt) key and launch Photos. From the resulting menu select 'Choose Library' and point at your iPhoto Library. It will do the rest.

If you prefer not to use Photos there are several 3rd party apps that you can use. Which to choose depends on the kind of photographer you are and your budget.

You should download the new photos app and transfer all your photos from iPhoto to Photos by using your iCloud backup data or Apple ID

Don't mean to argue with you my friend, but it is important to try and correct erroneous information.

but I was trying to say that you could access your photos from iCloud backup and transfer them to photos.

This is incorrect. iPhoto has no facility for making an "iCloud backup". iPhoto had no ability to store files on iCloud. There are no images there to 'transfer to Photos.' All of this ability comes only with Photos.app.

And yes iPhoto does have iCloud

And no, it does not. I wonder if you are confusing iPhoto, which was discontinued 5 years ago, with Photos the app that replaced it. Some of what you say might be possible with Photos. None with iPhoto.

Sorry for my mistake but English is not my first language and I make a few mistakes but I was trying to say that you could access your photos from iCloud backup and transfer them to photos. You will need to use your Apple ID to access iCloud if you haven’t signed in. And yes iPhoto does have iCloud

There is no iPhoto back up in iCloud. iPhoto had zero awareness of iCloud. What you suggest is simply not possible. Equally, I have no idea why you think your photographs are stored with your AppleID. They're not.

Nothing like an out-of-context screenshot to demonstrate... well what does it demonstrate really? This refers to features like photo stream and shared albums. Here's the real question: How many images does iPhoto store on iCloud? A round number will do. Oh, I know a round number: Zero.

What you're suggesting will not work. If it does, demonstrate it for us. If you can't then stop adding confusion, it's not helpful to others seeking assistance.

Not to mention that you would have little luck finding the Photos App to "download".