Un recognize font

I get pdf file and usually the font isnt regular one, most of the time when I edit the file with Adobe Acrobat Pro and copy/paste the text inside the font or when i change the font the text destoryed, also when i try to read the text with libaries in python/Node.js.

What can be the problem? I need to install the font on my computer and if yes than how?

For example: 

copying "סה"כ תשלומים" with David font and paste result: íéîåìùú ë"äñ

copying with font Times New Roman successed

copying with Times New Roman-13299 and paste result: tlli1n7 l:ltll tll17n