I want to use <h1> tags in my header but I do not want the text to be huge like the default <h1>.

I have tried something like:
h1 {
font-size: 11;
}

Also whenever I have h1 I dont know why but the content does not remain in one line

Say

This is something that should not be in h1 and<h1> this should be in h1</h1>

Outputs

This is something that should not be in h1 and
this should be in h1

But I want it to be

This is something that should not be in h1 and this should be in h1