How can I access my photos in iCloud?

You can see your iCloud Photos Library on a Mac, iPhone, iPad in the Photos.app, if you enable iCloud Photos. See: https://support.apple.com/en-gb/HT204264

On a mac or an iPad you can also see the iCloud Photos Library at the web page www.icloud.com, but using the Photos.app will be much more convenient. In Photos for mac you can create search for photos or adjust the photos, add titles, keywords, and more.

See the section get started in the article https://support.apple.com/en-in/guide/icloud/mm8b32f3ae27/icloud

To view photos from Mac see the article https://support.apple.com/en-in/guide/icloud/mm73262d11fe/icloud

Viewing photos can be directly seen https://support.apple.com/en-in/guide/iphone/iph3d267610/ios from iPhone when photo box is turned as on https://support.apple.com/en-in/guide/iphone/iph961b96c4d/ios

From viewing photos from Mac the photo library and its preferences is to be set , see this also https://support.apple.com/en-in/HT207368