There is already a register page created by the Learndash But to make it live over the page follow some steps.
>>Create a page with the name Register and save.
>>Click on the ‘+‘ mark and add the LearnDash Login option to that page.
>>Now set this page as a register page from the menus.
>>After setting this page to the register go to the LearnDash settings and Switch on the option Login & Register.
This is what you will see after logging out from your default user to a normal site.
You are done with setup of the signup page.