As a process I apply patches locally first, then using git upload the update(s) to a development site on the server.  Once the testing has been completed, the final step to apply the patch to the production site.   Using Terminal or your preferred shell program, navigate to the correct directory.  Then run this command using the name of the patch file (example.patch): patch < example.patchHowever, if you are patching Drupal core then remember to patch from the root directory...

In Drupal 8.x hiding the subject line is a quick task. In the admin area of your site go to structure > comment types > {comment type} > manage form display and the URL will be like https://domain.com/admin/structure/comment/manage/{comment}/form-display.  I have put the type in braces as you might have several comment types.  If you only have the default Drupal setting, then use default comments and the path will...