So you cant even ask for a desired username??

we are using this as a sign up form and asking for a desired username and desired email address. Not asking for any passwords. 

Unfortunately no. Username is considered as part of login credentials and asking for user login credentials is against JotForm Terms of use. 

Phishing. You agree that Company may terminate your JotForm Service immediately if a form's purpose is found to be deceptively obtaining: sensitive credit card information, social security numbers, user login credentials, or other sensitive personal information. All these activities are considered as Phishing and any account along with the violating forms will be suspended immediately.

Collecting Sensitive Information. You may not use the JotForm to collect certain types of sensitive information, including but not limited to credit card information and any type of login credentials. You may collect some sensitive information such as social security numbers or driver’s license numbers, but you are required to use best security practices of JotForm including SSL and Encrypted Forms features. You are solely responsible for compliance with any data protection and privacy laws and rules applicable to the sensitive information.

We also have a phishing system that is programmed to automatically suspend any account that has created a form which have a field that is asking for user login credentials.

Feel free to contact us if you have any other questions.