Hello,
First of all thanks for choosing our Theme, we are glad to be you in the WoodMart WordPress family :).
This is the custom menu added in the Top header. Please edit the Header from Woodmart >> Header Builder >> Edit the Header which you are using for the site >> then Add the Secondary Menu Item and then select the menu which you want to show. https://ibb.co/zZ6f10R
And the Login/Register already showing on the site. You have to open the site withou login or log out the user or see the site in the Incognito Browser then you will see the Login/Register button.
Best Regards.