Re: "apple icloud password : when i try to update or download a new app ,the app store asks for my password and when i type it (which I ** certain that is correct), it shows me that it’s incorrect".
Apple ID is now Apple Account. You can still sign in with the same email address or phone number and password.
Wondering whether it is your Apple Account password that you are entering in App Store, as required.
(ie: A correct device or computer log-in password is not correct for use in the App Store)
Your Apple Account is the one account that you use to access all Apple services and make all of your devices work together seamlessly. After you log in, you can use the App Store, iCloud, iMessage, Apple Music, Apple TV+ and more.
You might want to check that you are signed in to your computer or device with correct Apple Account details:
See how to: Sign in to your Apple Account on the web or in your device settings - Apple Support
What to do: If you forgot your Apple Account primary email address or phone number - Apple Support
and / or
If you forgot your Apple Account password - Apple Support
If needed: You can also check whether any restrictions are sst for the app store:
Manage App Store purchases, settings, and restrictions on iPhone - Apple Support
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Re: "Also tried to sign in on the website same thing happens".
Wondering in which sign-in webpage you encountered the incorrect password error (iCloud / Apple Account ?)
You can check or edit details in your Apple Account online:
Apple Account sign-in: https://account.apple.com/
If needed: How to: Get a verification code and sign in with two-factor authentication - Apple Support