To enable sending invoices and documents via email in BUSY, you can follow these steps:
1. Go to Administration > Configuration > Features and Options > Email.
2. In the Email Configuration window, enter your email settings, including the SMTP server details, email address, and password.
3. Click on the "Test" button to verify the email configuration.
4. Once the test is successful, click on the "Save" button to save the email settings.
5. Now, you can go to the respective module (e.g., Sales, Purchase) and select the invoice or document you want to send via email.
6. Click on the "Email" button or option, and the software will automatically generate an email with the attached document.
7. Review the email and make any necessary changes.
8. Finally, click on the "Send" button to send the email with the invoice or document attached.
Please note that these steps may vary slightly depending on the version of BUSY you are using.