Default font (used by PDF library) doesn't support all UTF8 symbols.
So if you use Chinese,Arabic,Cyrillic,Hebrew -- you must install new font.
Please, use this way.
1. dowload zip from https://freefontsdownload.net/free-st-gigafont-typefacescode2003-font-152444.htm
2. run ftp client and create folder "fonts" inside active theme
3. upload file Code200365k.ttf to folder "fonts".
4. add following PHP code to functions.php
add_filter("woe_formatter_pdf_use_external_font","__return_true"); add_filter("woe_formatter_pdf_apply_external_font",function($fpdf){ $fpdf->setFontPath( dirname( __FILE__ ) ."/fonts/"); $fpdf->AddFont( 'Code200365k', "", "Code200365k.ttf" ); $fpdf->AddFont( 'Code200365k', "B", "Code200365k.ttf" ); $fpdf->SetFont( 'Code200365k', '', 12 ); return $fpdf; });