How to change email subscription confirmation on my website?

Hi,

How do I have a “submit button” and replace the email entry box with “Thank you. Your email has been added to our list!” after someone submits?

My website is www.buddings.co

You are referring to the newsletter footer?
Yu can use if/else:
{%- if form.posted_successfully? -%}
Thank you. Your email has been added to our list!
{%- else -%}
submit button
{%- endif -%}
Hope it helps!