If you have opened a web page and the text is too small to read you can make it bigger. I will use the Wikipedia webpage as an example. If I look at Wikipedia in the Browse Activity it looks something like this :

I can now enlarge the text by first clicking on the View tab at the top of the page (below the Location Bar) :

At the top left are some icons that look like magnifying glasses :

If you click on the magnifying glass on the left the text on the webpage will get smaller. If you click on the one on the right the text gets bigger. You can click as many times as you want until the text is the size you desire. If I click several times on the enlarging magnifying glass my Wikipedia text gets very big :

Full Screen

We can also force the Browse Activity to use more of the screen when displaying web pages. To do this press the Full Screen icon at the top of the View Tab (next to the magnifying glasses) :

The web page will now take up all of your display. To return to the 'normal' view you need to click on the same icon as it appears at the top right of the web page :