Unexpected password prompt for app download on iPhone

Re: "When I want to downlaod an app, II dbl click my iPhone and it starts. But, for some reason, today, my password was required ... ,"

You may want to check you are signed in to your device with your correct Apple Account ID and password:

See how to: Sign in to your Apple Account on the web or in your device settings - Apple Support

Seems you may have a setting in place that requires a password for downloads from the App Store:

You might want to check your App Store settings:

See: Require a password for purchases in the App Store and other Apple services - Apple Support

and

See how to: Manage App Store purchases, settings, and restrictions on iPhone - Apple Support

_____________________________________________________________

Re: " AND my password was rejected. I know it is my proper password."

Wondering which password you entered.

Eg: Seems it would be your Apple (ID) Account password, and not iPhone log-in password that was required.

If you changed that Apple Account password since you last used the App Store, you may need to sign out of the App Store (may be still using the old password). and sign back in with the current password,