You can send invoice emails to your clients in bulk by following the steps below:
Click on "Billing" and then click on "Invoices".
Using the date range filter at the top of the table, select a date range and click "Go".
Using the checkboxes on the left-hand side of the table, select which invoices you'd like to email.
This will cause a "Send Email Type" dropdown menu to appear at the top of the table.
Use this dropdown menu to select the email template you would like to email to your clients and click “Submit.”
"Send Email Type" Options
Send New Invoice
This option will send the selected clients the "New Invoice" email template.
Send Invoice Reminder
This option will send the selected clients the "Invoice Reminder" email template.
If you're using the Custom Invoice Email Templates Add-On and created additional invoice email templates, they'll also be listed as options and will be displayed by the "Template Title" you've set.