If you want to use the Enhanced Lookup in SharePoint 2013 or SharePoint 2016 you have to change the render mode of the form web parts in the new-form, the edit-form and the display-form to ‘server render’. Otherwise it’ll look like an ordinary lookup field.
Open the form page, click on “Edit Page”, edit the web part and change the “CSR Render Mode” to “Server Render” in the Miscellaneous section. This has to be done in all forms of the list where you want to use the Enhanced Lookup (New, Edit, Display).
In list settings click on create column. The create column page now offers a new type “Lookup (information already on this site, including search form)” in the name and type section. Enter a name select this type and click on OK.
Select the web site which contains the list where you want to lookup items and then select the list.
Configure the fields which will be searched when the input is verified or when items are searched for using the search dialog.
Select the fields to be displayed in the search dialog. These columns will be displayed as tables in display forms.
Select the column to sort by and select the direction. To configure the sort order in list views select the same column that is configured in the “in this column”. Tip: Create a calculated field containing the sort column plus title e.g. ‘Date’ & ‘Title’.
Select content types from the list of available types and specify the scope of the filter.
From the open hyperlink drop down select “Same Window”, “New Window” or “Modal Dialog”.
Select display as table and select the display sum checkbox to show totals for number fields. You can configure the used in list views if multiple values are selected. Using <br/> will insert a line break after each link.
Check the new, edit and display check boxes to display links in forms and enter a link title e.g. ‘Click to add a new customer’.
Select the lookup fields to synchronize with or select ‘create new lookup field’.
Under site settings in the site actions section click on manage site features. Look for the feature named “Sapiens.at.SharePoint interlink lookups” and click on activate.