How to the enlarge the font size of a journal paper
If the paper is in PDF (the standard) you can print using the Poster option. You will need to print the page in a bigger size, to make it fit in multiple pages. 

https://helpx.adobe.com/acrobat/using/basic-pdf-printing-tasks.html

You can try to convert the PDF to word and enlarge the font before printing, but many don't convert well.

https://smallpdf.com/pt/pdf-para-word