A contract may be express, implied-in-fact, or implied-in-law.
An express contract is one in which the terms are stated orally or in writing. An implied-in-fact contract is one in which its existence and terms are manifested by conduct.
The distinction between an express and an implied-in-fact contract relates only to the manner in which the agreement is shown. Both are based on the express or apparent intention of the parties.
[An implied-in-law or quasi-contract is an obligation imposed by law to do justice even though it is clear that no promise was ever made or intended. The essence of an implied- in-law contract is the receipt of a benefit which would be inequitable to retain without paying for it.]