I’ve made a html document in Rmarkdown, it works just fine when I open it on my computer, but as soon as I sent it via e-mail (to myself, for example), it doesn’t show graphs and the comments seem unreadable (the comments are in latvian). How to solve this issue?

I tried to google the problem, but I didn’t find anything useful to my case. As of comments I set lang:lv-br at the start of the document, but it didn’t change anything.