Post Font and Content heading fornt

mai apne site ke liye Newspaper theme use krta hu. mai isme font ko kaise optimize karu. kaun sa font ek post ke liye hona chahiye uska size kya hona chahiye. Content ke heading ka font aur uska size kya hona chahiye. iske uper full guide kare.
isko kaha jakr change kare taki font ka size implement ho sake mere site par. please step wise samjhaye.
Chandan sir se request hai ki aap iske uper bhi ho sake to ek video banaye youtube par.