How do I share iCloud photos when unable to access Apple Store account?

Did you set up iCloud Photo on your Mac as described in this article?

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1. In the Photos app on your Mac, choose Photos > Settings, then click iCloud.
2. Select iCloud Photos.
3. The photos and videos in the Photos app on your Mac are added to iCloud. Also, any photos and videos already stored in iCloud Photos are now available on your Mac.
4. Note: If you have multiple photo libraries on your Mac, iCloud Photos keeps only the photos and videos in the System Photo Library up to date.
5. To view photos and videos stored in iCloud Photos, open the Photos app, then click Library in the sidebar. All the photos and videos you see are stored in iCloud Photos.

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copied from: Set up iCloud Photos on all your devices - Apple Support

If yes, are you getting any error message, if you want to log into your iCloud Account?

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• Sign in to your Apple Account: If you’re not signed in to your Apple Account, choose Apple menu -> System Settings, then click “Sign in” at the top of the sidebar. Enter your Apple Account email address or phone number, then enter your password. Click iCloud, click Photos in the list of apps, then turn on Sync this Mac. If you don’t have an Apple Account, you can create one.

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copied from: Use iCloud Photos on Mac - Apple Support

If you can use iCloud Photos successfully, can you create a shared photos library or shared albums as well?

Share photos and videos and keep them up to date with iCloud - Apple Support

If you have turned on "Optimize Storage" in Settings>[name]>iCloud>Photos, then your pictures aren't fully contained on your phone, and you have to have access to your iCloud account to work with them. You can view the pictures on the small iPhone screen, but the full pictures are still at iCloud.

If you don't use Optimize Storage, then you can use the share menu "Share" menu.

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