There is no drop-down or such feature. You have to c rate the url yourself. Howeveer, you can use the OpenAs plugin to create a form to use as in interface to the newpagetemplate plugin;
https://www.dokuwiki.org/plugin:openas#expanded_syntax_for_the_openas_format
There is also the Add New Page plugin:
https://www.dokuwiki.org/plugin:addnewpage