The contract and agreement can be thought as the same thing however there are some differences between contract and agreement.
A contract is a vocal or printed agreement between two or more organizations which is by law. An agreement is a verbal and written contract between two or more companies without legal involvement. In other words, we can say that the contract is an official document while agreement is a non-official document. Agreements are normally for small things and a contract is a formal agreement for business purposes which includes important matters with legally binding.
Contracts are of many kinds such as contract between debtor and lender and the contracts for projects between client and the company. There are other contracts including building contracts, service contracts etc. Marriage is also a contract between husband and wife. Agreements are verbal and are based on personal understandings and trust without the involvement of law. There is no legal guarantee in agreement. Agreements are commonly made between family members or close friends.
Contracts involve a general approval of the terms and the conditions are believed likely to reach by all organisations and companies. Agreements have common approval but there is no guarantee of promises by companies and it can be modified at any time by any individual.