When we add a user from the /designer interface, how long is the temporary passw

Appian allows us to configure following two properties using Appian Administration console. To answer your question, please read Maximum Temporary Password Age that says upon temporary password expiration for the first time users, they will have to request system administrator to reset the password.

Expire Temporary Passwords - Should auto-generated passwords, such as those generated when a new user account is created or when an administrator resets a user's password, expire? The default is that they should expire.

•Maximum Temporary Password Age - The number of minutes after which an temporary, auto-generated, password expires and is no longer valid. When a temporary password expires, the user is not allowed to log in and must request that an administrator reset the password. The default is 10080 minutes, which is one week.

For more details, please refer Appian Administration Console documentation.
forum.appian.com/.../Appian_Administration_Console.html

Thanks! This is exactly what I was looking for.