CRM OOB feature allows adding single attachment to the Email activity, but the functionality of this solution enhances the Emails to get multiple attachments on a single click, as compared to the conventional method of having one attachment to the email
The functionality is explained briefly here:
Create an Email activity and save the record.
Upon saving the record you can able to see the below tab. Please see the below screenshot.
Click on Select files. This will pop up with the list of files to upload. select the multiple files by clicking on the
Shift or CTRL key.
Click on Open. Then select the submit button.
The added files will be shown in the Attachment area.
