Thank you for asking this question
All agreements are not contract, but all contracts are agreement, it is true according to section 2(h) of Indian Contract Act , 1872 which says "An agreement enforceable by law becomes contract".
Section 10 of Indian Contract Act -" All agreement are contracts if they are made by the free consent of parties competent to contract, for a lawful consideration and with a lawful object, and not hereby expressly declared to be void".
The following essentials alements must co-exist in order to make a valid contract:
1. Proper offer and proper acceptance with intention to create legal relationship.
2. Lawful consideration
4. Free consent
5. Lawful agreement
Hope this will help