You can use iCloud from anywhere by signing in to iCloud.com from a web browser recommended in the Apple Support article System requirements for iCloud.
Note: Not all iCloud features are available on iCloud.com in an iPhone browser. Sign in to iCloud.com using an Mac or Windows computer browser or an iPad browser to access more features.
Sign in to iCloud.com
Sign in to iCloud.com using two-factor authentication or two-step verification
Go to iCloud.com, then sign in with your Apple ID (the one you use with iCloud).
Follow the onscreen instructions to verify your identity by entering a code sent to a trusted device.
You must verify your identity this way to use any web app except Find My iPhone. You can use Find My iPhone by tapping it after entering your Apple ID.
Note: During two-factor authentication or two-step verification on iCloud.com, you can choose to trust the browser so that you won’t be asked to verify your identity the next time you sign in.
Switch to a different iCloud.com feature
At the top of the iCloud.com window, tap the name of the feature you’re currently using, then tap another feature.
If you have web-only access to iCloud.com and you are on an iPhone, you only see Notes. To see and use other iCloud features, set up iCloud on your iOS device, iPadOS device, or Mac.
Sign out of iCloud.com
Tap your name at the top of the iCloud.com window, then choose Sign Out.