Clicking on sign out does that remove stored username and passwords on iPad?

When you sign-out of iCloud on a device, you will be offered the option to keep a copy of some iCloud data (such as Contacts, Calendar and Keychain) on your device.

Your response will determine whether a copy of this data is retained, or not, after logout from iCloud.

This raises the question as to your objectives in logging-out from iCloud? If your intention is to prepare the device for a new user (and, by extension, to ensure that your personal data is removed from the iPad), log-out from iCloud alone is insufficient to data-cleanse the device.

If you can provide some information as to your objective, appropriate advice can be provided.

To remove user names and passwords for sites you’d need to go into the settings, accounts and passwords and delete them.

I’m not sure if you can do them at once or one at a time.