How do you access photos stored on your iCloud account?

Once Apple ID and its password is signed in and photos are synced with iCloud Use iCloud Photos on iPhone - Apple Support , they can be directly accessed from iPhone see the articles View photos and videos on iPhone - Apple Support

Search for photos on iPhone - Apple Support

Browse photos by location on iPhone - Apple Support

You can either access the photos at the iCloud web page www.icloud.com using the Photos.app on this page. On the iPhone the problem is, that this web page defaults to the mobile version of this page, which is very different from what you get on a computer. You will need to request the Desktop Version of www.icloud.com in the browser on your iPhone, see: https://appleinsider.com/articles/20/04/02/how-to-automatically-request-a-desktop-version-of-a-website-on-ios

• Go to the website in Safari on your iPhone
• When it has fully loaded, tap the aA icon in the address bar
• From the menu that appears, choose Request Desktop Website

Do this and the site will change to the regular, full, Mac-style view — probably. In all cases, your iPhone will believe that it has switched, as you'll see if you go to change it back.

• Tap the aA icon in the address bar
• Choose Request Mobile Website

The easier way would be to enable iCloud Photos on your devices and luse the Photos.app to browse your iCloud photos. It will be much more versatile, as it will allow you to search the photos and add adjustments and captions.