To ensure billing is correct for your imported members, make sure you specify the membership level and renewal date for the members when you import them.
By default, imported members will be set to Unassigned/Manual Billing as their
billing option. There is no need to change the billing option for the
members. Your members will be prompted to change their billing option
when they sign in to renew or update their billing information.
There is no default passwords for imported members, and there is no need to set one for your members. Simply guide them to the Member Manage page to login. There they will be able to request a password to be emailed to them right away using their email address.
If a member fails to receive their password email, you can set a
password for the member manually - pull up the member's account, then
click to the Profile tab. Locate the password field, and click Change. Enter a password and click Save.