How I can adjust these for responsive/mobile screens

Hi Elena,

For 1, go to customizer > typography > Header, you can change the font size for mobile by clicking on the mobile icon:
https://www.screencast.com/t/OrDNnAnE2YPt

For 2, just checked the Search template, don't see the same issue.
https://www.screencast.com/t/zOMNATdlDIx
https://www.screencast.com/t/NKhSimTw6

I'll have to see your site to define what the cause is.

You can use the private information field.
https://docs.generatepress.com/article/using-the-premium-support-forum/#private-information

Let me know :)

And here's a walkthrough video of Search template, hope it's helpful to you：
https://youtu.be/QIN0EaPllO4

Thank you Ying for issues on 2) I am adding the login details in the private information below.
THANK U

For issue 2, it seems just the word is too long and the default setting is not to break the word.

You can try this CSS:

.gb-headline {
    word-break: break-all;
}

oR this CSS,

.gb-headline {
    word-break: break-word;
}

To see which one is working better for you :)

Adding CSS: https://docs.generatepress.com/article/adding-css/