Select the Email tool from the Tool Menu of your site.
Click the Permissions link.
Modify the permissions for the roles listed.
Check the box next to each permission you would like to allow for a given role. (Deselecting a box will remove the corresponding permission.)
Click Save to save your changes.
Note: You may see different roles listed depending on the roles that exist in your site. A role must be present in the site in order for you to modify its permissions.