Changing share button email text

The value is defined by the label "LBL_RECORD_SHARE_BUTTON" in the primary language file. You should be able to modify it via a language extension.

See here for more info on language extensions: http://support.sugarcrm.com/Documentation/Sugar_Developer/Sugar_Developer_Guide_7.6/Extension_Framework/Language/

Create or modify file in \custom\Extension\application\Ext\Language\en_us.lang.php :

Add this:

$app_strings['TPL_RECORD_SHARE_SUBJECT'] = 'Shared {{module}} {{name}} from {{appId}}';
$app_strings['TPL_RECORD_SHARE_BODY'] = 'Please checkout {{module}} {{name}} from {{appId}}';

Now you can change this text.