I don’t see a Photo Stream on my Photos app on iPad or iPhone
I don’t see anything that’s called Photo Stream in any of my photo files or apps.
iPad Pro, iPadOS 15
Question marked as
The very old My Photo Stream service is being closed-down by Apple:
Information about the My Photo Stream shutdown - Apple Support
My Photo Stream has been replaced by the far superior iCloud Photos:
Set up and use iCloud Photos - Apple Support
If you don’t see My Photo Stream in iPad settings, you have not previously used this service with your current AppleID. If available to you, the setting will be found here:
Settings > [Your Name / AppleID] > iCloud > Photos > My Photo Stream
If the setting isn’t visible, the service is no longer accessible to you. If the My Photo Stream service is still available, you will only be able to access and archive existing photos prior to total service closure that will occur in a few weeks.