In visible mode of editor in wordpress page, <ul> <li></li></ul> are not working for listing at the time of content entry.
Please suggest any solution
For the visual mode of the content editor, you will either want to use the WYSIWYG editor, which has unordered list and ordered list options (similar to this Tickey content editor - Bold, Italicized, List, Image, Link, etc.).
From there, if you prefer to use html (which you've indicated), you can navigate to the text option for the editor.
Both of these options are native to WordPress and not theme specific.
Alternatively, you can also use Visual Composer to manage your content.