Inkjet and laser prints don't have font sizes like older dot-matrix printers did, so changing the font size requires changing it in the document editing program prior to printing. In most cases, highlighting the target text and selecting a larger font size is easiest way to change the font's size.
When printing a website or PDF document, there might not be a clear way to change the font size. One option is to copy the text and paste it into a word processing program. The key sequence "Ctrl+A" selects all the text, and "Ctrl+C" copies it. Users can then paste it by typing "Ctrl+V" in the word processing program. Another option is to choose the "Printer Settings" or "Properties" menu option within the program, if available. By choosing the "Fit to Page" or "Zoom" option, users can often increase the text size.
Older dot-matrix printers used a discrete set of characters, much like typewriters. While some later models allowed users to choose between different styles of fonts, most were bound to certain character dimensions. Later printers, the basic designs of which are still used today, are able to print any set of pixels up to a certain resolution. As a result, they can print any font that software can convert into a printer document.