I've installed wordpress Version 4.9.8 with civiCRM.
Now i have create one new menu name is "userdata"
But when i click on menu "Userdata" it will redirect to the dashboard. Instead of dashboard it will show userdata add form.
Drp, Welcome to stackexchange!
I guess userdata link is the one you have created through extension/plugin and is also registered using xml and have menu rebuild. When menu link is not registered in CiviCRM it will default redirect to CiviCRM dashboard page.
If you haven't registered than