How do I create a custom template for view?
Below give are the views template suggestion allowed in Drupal 8.


views-view--foobar--page.html.twig
views-view--page.html.twig
views-view--foobar.html.twig
views-view.html.twig
views-view-unformatted--foobar--page.html.twig
views-view-unformatted--page.html.twig
views-view-unformatted--foobar.html.twig
views-view-unformatted.html.twig
views-view-fields--foobar--page.html.twig
views-view-fields--page.html.twig
views-view-fields--foobar.html.twig
views-view-fields.html.twig


Refer Views template files for more information.