How to globally increase font size

[jerome2792435775q4]

I'm trying to format a book to be more accessible for my students by increasing the font size. The only way I can do it is by individually changing each block of text, which sounds very time-consuming. But I'm all thumbs when it comes to computer stuff, any advice?

[try67]

This is not the kind of edit that should be attempted on a PDF file, it was not built for it. This change needs to be implemented in the original file, and then a new PDF file should be created.

[Luke Jennings3]

If I understand correctly, you have a pdf book and you want to print it with larger type? I assume you want to print, as a pdf can be viewed at any magnification (you can set the initial view magnification under File> Properties). Changing the font size should be done in the original application (as already mentioned) and will likely cause text re-flow and the need to add additional pages, unless the size change is minor. 

Another option would be to print larger, or scale the page content using a preflight profile, but that would only work if there are ample margins around the copy.

[jerome2792435775q4]

not quite, i'm trying to make the font bigger, as you would on a google document, like pressing ctrl+a and simply increasing the font that way, but there are different bodies of text for each page, so I was trying to find out how to increase the font size globally.