change individual title wordings and color in header

You can do it for that page by adding the following CSS code in the Custom CSS option of your theme on the below path.

Admin Area -> Appearance -> Customize -> Additional CSS

.postid-337 .header-image-bg .page-title {
    color: #fff !important;
}

To do the same for other pages individually you have to copy the above code and change the post ID 337 in it.

To apply it on all pages you can use below CSS code.

.single .header-image-bg .page-title {
    color: #fff !important;
}

You can change the color value in the above code to whatever you want to use by referring the following pages.

https://www.w3schools.com/html/html_colors.asp
https://www.w3schools.com/html/html_colorvalues.asp
https://www.w3schools.com/tags/ref_colorpicker.asp