Trying to integrate a "Get in touch" button to the header of my website

Hello,

I am trying to integrate a "Get in touch" button to the header of my website. Website located here:

http://straat.design/

I need a similar "Get in touch button" integrated into my header as shown on this website:

https://www.bellahunt.com.au/

Do you know of a plugin which can do this? If not how could I integrate something like this into my site?

Cheers

Kim