It is often the case that PDF viewers cannot display the correct fonts for a document. This happens when the font mapping in the PDF file does not match fonts available on the machine.
Text may be badly spaced, look funny, or even be complete gibberish. The problem is caused by the PDF originator, not the viewer.
†The PDF format allows for fonts used in the source document to be included into the PDF file. Adobeís technical document describes the situation in some detail. https://helpx.adobe.com/acrobat/kb/font-handling-in-acrobat-distiller.html
The quick solution in your PDF writer/creator is to find the preferences options that describe the document fonts. Somewhere in there you will find settings to include or embed the fonts into the PDF file.
This will ensure that the recipientís PDF viewer does not need to locate the fonts on the local machine, it will find them in the file.
This will solve most of these PDF font problems.