Homepage link problems

Hello.

I just started my first wordpress page. It works great, however, when i link the homepage, for instance on facebook or messenger, a small window with the link of the page and some text appears. It is wrong. It says the name of another page on the site, and also “This is just a short excerpt about your blog.” I have tried to google this “excerpt” and changed that on other pages but there is no option to the homepage. I have 3 pages on my site, homepage and two others and I can only change those two others.
I would like to change it but I dont know how. Could someone assist me in where i can change this ?