To issue quotes to guest customers via direct links, enable guest quotes in the system configuration.
Keep in mind that the following options must be enabled, too:
To enable guest quotes:
Navigate to System > Configuration in the main menu.
Select Commerce > Sales > Quotes in the menu to the left.
For faster navigation between the configuration menu sections, use Quick Search.
Clear the Use Default check box.
Select the Enable Guest Quote check box. This enables the generation of unique links for sending quotes to guest users.
Click Save Settings.