WebApp like same look as WebPage

How I can make the heading on the web app bigger to fit a logo.

No 100% sure what you mean, but sizing and such things are controlled by Webstyles. Create a new webstyle and assign this to your heading text.

but can put like logo on the heading made look web page

Alexis, again not fully sure what you mean, do you have an example somewhere to look at or a screenshot?