Requesting sandboxes
Developers generally have admin rights on the non-production instance where Developer Sandboxes are allocated, and can thus allocate a sandbox to themselves.
However, if you don't have admin rights and need a sandbox, you should contact your company's ServiceNow administrator.
Get help now from your Now Support administrator
The ServiceNow admin in your company can help you with things like activating plugins, kicking off upgrades, unlocking accounts, updating user permissions, and much more.