Adding to Register page

For romanceheroesandnovels.com/register  .. How can I add the option of: “Have an account? Sign in:”

On my other site, which is buddapp theme: https://transencounters.com/register/   there is the “have an account? sign in” option I’m referring to.

In fact, I really like the register “form” on transencounters.com/register. It looks like the register form is contained within a box which is on a page, whereas this new romanceheroesandnovels.com/register page doesn’t look as good it seems more spread out throughtout the page. Is there any way to make romanceheroesandnovels.com/register look more like https://transencounters.com/register/ ? Perhaps there is a register shortcode I can put on the “register” page?

But more important is the first question of how to get the “have an account, sign in” option, I need that on the register page asap.