Contract vs. Quasi-Contract: Difference Please

Main to samajh nahin aata yeh dono concept, khair koi bata do. Mere paas to aayi thi yeh note ki Contract ka concept hain jo aane waala kaam ke bich jaan ke liye lagta hai, jaise ki if a person orders something online, tab aane wala kaam hai delivery. Lekin quasi-contract ka to kuch aur hoga. Pehle to koi Contract na lagaa, par phir bhi aane wala kaam hoga jaise ki, example ke liye, a person ke ghar ke andar se khada ho gaya hai, aur phir usse damage hua. Maine socha hai ki yeh quasi-contract ka concept hoga. Koi sahi hai?