You can send mass email to a maximum of 5,000 external email addresses per day per licensed Salesforce org based on Greenwich Mean Time (GMT), and sending email from list view is considered as mass email. For example, if you have email@example.com in your email 10 times that counts as 10 against the limit.
You can send mass emails only to contacts, person accounts, leads, and your internal users.
You can send an unlimited amount of emails through the Salesforce UI to your internal users, which include portal users.
To mass email from the list view:
- Select/create the list view
- Select the contacts/leads checkbox
- Click the "Send List Email" button, if you do not see the button, make sure the button is added to the list view and you have "Allow sending of List Emails" permission, see this blog for detail.
In the Send List Email window
- You will see the balance of send email limit remaining
- You can select "From" based on your setup, including Organization-Wide Email Addresses
- You can use an email template, merge fields, and attach files
- You can Send Later and Save as Draft
- Each recipient will only see their name as the recipient, not the whole recipient's name
Tips: to see your draft email, looks for "List Email" from the 9-dots icon