Hello,
WooCommerce > Settings > Accounts & Privacy > Account creation > Allow customers to create an account on the “My account” page – https://docs.woocommerce.com/document/configuring-woocommerce-settings/#section-15
Just add Cart element to the header structure (Theme Options > Header builder).
If you need any further assistance, provide temporary wp-admin access.
Here you can find videos about the Header builder – https://www.youtube.com/user/8theme/videos
Regards