My pdf file has deleted letters in the 'Preview' box of my Yahoo emails but appears as it should when it is downloaded. Not sure why it is happening and how to fix it? Many Thanks

The pdf document does not appear as it should in the "preview" section when i send it via email on Yahoo Mail. There are typos all over the place but when i open the document or download it from my email it appears fine, without any typos. A recipient of this email has also been in touch to let me know that it is appearing that way for her as well. I edited the word doc and converted it to a pdf on a Microsoft laptop and then saved it on to my Mac and I have been sending this document on email via my Mac - could this be part of the problem?