The system will create login credentials automatically for your clients in the following instances:
1. When you send an agreement to a prospect to be signed. If you didn't already switch the contact from prospect to active client and create login credentials for the contact yourself manually in the process, then after the client signs the agreement, the system generates and sends the login credentials automatically and also switches the status of the prospect to active client, so that s/he can login.
2. When visitors (prospects) purchase a product, the system automatically makes them buyers (as contact status) and generates login credentials for them. These login credentials are usually sent automatically to the buyers with the message 'How to access [product name]' that is added automatically to a new product autoresponder series when you create it in your cart, and scheduled to send immediately after purchase, unless you delete or edit this message to repurpose it.
In the rest of the cases (you create contacts manually or import them, also when people register or subscribe via an Opt-In Form), they are initially prospects without login credentials.
If you switch them manually to active clients or hot leads and create credentials, you can send them the login credentials via Contacts > Contact Name > link 'edit info' in the top right corner > in the 'Edit Personal Profile' pop-up window > section 'Contact information' > you can use the link 'Send reset password link to client' to send them an email containing the login info.The system is using the 'Password reminder' template for this email, template found in My Account (top right corner) > Notification Templates.
Also, in all messages you can use the $USERNAME$, $PASSWORD$, and $LOGINLINK$ replacement tags to send the login credentials to the client.