Safari for Mac: Zoom in on webpages using Safari
You can make text and images larger so they’re easier to view.
Make the content larger for all webpages: Choose Safari > Preferences, click Advanced, then click the Page Zoom pop-up menu and choose a percentage.
Make the content larger for a specific website: Choose View > Zoom In, or press Command–Plus Sign (+), or pinch open on a trackpad that supports gestures. Safari remembers the zoom level when you return to the website (unless you pinch open to zoom). To make only text larger, press Option while you choose View > Make Text Bigger. Safari remembers the text size when you return to the website.
Expand to full-screen view: Click the green full-screen button 
in the top-left corner of the browser window, or press Control-Command-F. To stop using the app full screen, move the pointer to the top-left corner of the screen, then click the green full-screen button again, or press Control-Command-F.
Use Safari in Split View: Click and hold the green full-screen button in the top-left corner of the browser window, drag the Safari window to the side of the screen you want, then release the button. Select an app that supports Split View on the other half of the screen.