How do I generate an email with my invoice/bill through the BUSY portal? Where can I find and print this email with the attached invoice/bill PDF?

If you require to share the Invoices through BUSY by Email then follow the steps as mentioned below for Email Configuration: 
Step 1 : Go to Administration 
Step 2 : Click on Configuration tab 
Step 3 : Select Email Configuration 
Step 4 : Here you will get the Sending options so select the same accordingly like Send Directly or Microsoft outlook or Thorugh outlook express 
Step 5 : If You will choose Send through Microsoft Outlook or Outlook express then the same email should be configured in your system as default email sender 
Step 6 : If you select the option Send Directly then you need to specify SMPT Server along with User name and Password 
Step 7 : Here the password should be generated through app password facility of your email account such as for gmail 
Step 8 : After the specifying all the details you can check the test email 
Step 9 : If the same is sucessfull then open any invoice in modify mode and go to the email tab and check the email sending through Invoice.
To generate an email directly for your invoice through the BUSY please follow below steps : 
Step 1: Go to Administration. 
Step 2: Go to Configuration. 
Step 3: Click on voucher series configuration. 
Step 4: Then select voucher type and series. 
Step 5: Then press Alt+c and or click on voucher Configuration. 
Step 6: Specify Y for Send Email after saving option. 
Step 7: Then save the configurations.