I want to override
\magento\module-user\view\adminhtml\templates\admin\fotgotpassword_url.phtml file without creating a custom module.
Can you please help me How do I solve the problem?
You have to create a adminhtml theme to override this phtml. you have the steps in this link: How to create admin theme for magento 2
It is not possible with create custom module or custom Theme for admin.
My Suggestion is that a create custom module and changes template from this module.
One of advantage of this process, you can use this module for any module template override.