Hello, I really think that this page (How to contribute) should make it very clear how to submit a feature request, because at this moment it's not clear at all how to do it. Thanks.
Topic on Talk:How to contribute
Hi @Ark25, we want to keep this page simple at a high level. Starter kit (the first link in this page) mentions that "Phabricator is where all the bugs of MediaWiki Software are reported and suggestions for new features and enhancements are given." Searching for "how to submit a feature request" provides a first result to Manual:FAQ#I.27ve_found_a_bug_or_have_a_feature_request._Where_do_I_post_it.3F.