With the Acrobat and Acrobat Reader DC October 2018 release (19.008.20071), we have introduced a Unified Sharing experience that allows you to easily invite people for collaborating on documents across desktop, mobile, and web. The new experience enables you to share documents using any of the following methods:
- Send personalized invitations using the Document Cloud Share option. You can send a document for review so that recipients can comment or view only.
- Send an anonymous or public link in an email.
- Send as an email attachment.
With the new unified sharing experience, the existing Send, or Attach to Email entry points, like the Email icon 
in the top bar now takes you to the new unified share pane. We encourage you to use our new sharing options.
However, if you use Send documents as attachment frequently for your work, you can change the behavior of the Email icon to one-click Attach to email experience using the registry/plist file mentioned below. After applying this fix, you can continue to use the Adobe Document Cloud sharing options, using the Share button in the top right.
Note:
A preference to set the email icon to one-click attach to email experience will be added in a future release.
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