Add text & make logo larger in header

How can I make the text white?

Add this CSS:

.nav-text {
    margin: 0 auto;
    color: #fff;
    font-size: 18px;
    font-weight: 600;
}

I included font size for and font weight properties you can remove or adjust to suit.

Just need to decide whether you want to keep the text on mobile.
If you want to remove it on mobile then edit your HTML so this:

<p class="nav-text">Free USA USPS First Class Shipping</p>

becomes:

<p class="nav-text hide-on-mobile">Free USA USPS First Class Shipping</p>

Thank you. I've noticed with the text hidden on mobile and viewed in portrait mode (on landscape on an iPhone 12pro max it's not recognized as mobile), the logo isn't left justified. Is it possible to make it left justified for that instance? On the desktop and mobile in landscape mode, it is left justified.

Oops - was meant to add this CSS as well:

@media(max-width: 768px) {
    .main-navigation .navigation-logo {
        margin-right: auto;
    }
}

That worked. Thanks!

Glad to hear that