Adding icon button to Main Nav Menu

This can be accomplished with a custom CSS file preferably used in a child theme. Without a site link, it would be unlikely we could even guess at how to go about it.

This can be easily achieved with CSS.
To point you in the right direction…

.menuclass ul li:last-child
{
color: #ffffff;
}

This will format the last list item on a ul.

Assuming the default css?

Hi!
Thanks for the help, I’m working on it!!
The site is
https://safefoodfoundation.org/ftp3/wordpress/
What I’m trying to do is make the ‘donate’ button look like either a veggie or a fruit.
I’ll see how I go

I ended up just changing my theme to a new theme with a built in donate button!