As I understand:
Bank is a formal source where we deposit pura extra money and can be taken when it is in demand with some increase in money ..
three main functions of bank are :
1) It provides loans to the rich as well as small farmers for their cultivation.
2) it added some interest on the money which was deposited in Bank by person for safety and returned by bank with some extra amount
3) it provides our money safely as if any distraction caused in bank still our money doesn't goes in vain we got it .

Bank:
A bank is a financial institution that provides a wide range of services to individuals, businesses, and governments. Its primary function is to facilitate the flow of money in the economy by accepting deposits from customers and providing loans and other financial services.

Main Functions of Banks in the Modern Age:

1. Accepting Deposits:
One of the main functions of banks is to accept deposits from individuals, businesses, and other organizations. Banks offer various types of deposit accounts such as savings accounts, current accounts, fixed deposit accounts, etc. These deposits serve as a source of funds for banks, which they can then use to provide loans and other financial services. Deposits also provide a safe and convenient way for individuals to store their money and earn interest on their savings.

2. Providing Loans:
Banks play a crucial role in providing loans to individuals and businesses. They offer various types of loans such as personal loans, home loans, business loans, etc. Loans provide individuals with access to funds for purchasing homes, cars, and other assets, while businesses can use loans to finance their operations, invest in new projects, or expand their businesses. Banks assess the creditworthiness of borrowers and determine the terms and conditions of the loans, including the interest rate and repayment schedule.

3. Offering Financial Services:
In addition to accepting deposits and providing loans, banks offer a wide range of financial services to their customers. These services include:

- Payment Services: Banks facilitate the transfer of funds through various payment methods such as cheques, debit cards, credit cards, and electronic transfers. They provide a secure and convenient way for individuals and businesses to make payments and receive funds.

- Investment Services: Banks offer investment products such as mutual funds, stocks, bonds, and other financial instruments. They provide investment advice and help individuals and businesses manage their wealth and achieve their financial goals.

- Foreign Exchange Services: Banks facilitate currency exchange and provide services related to foreign exchange transactions. They help individuals and businesses convert one currency into another for international trade and travel purposes.

- Insurance Services: Many banks offer insurance products such as life insurance, health insurance, and general insurance. They act as intermediaries between insurance companies and customers, providing insurance policies and handling claims.

- Advisory Services: Banks provide financial advisory services to individuals and businesses. They offer guidance on financial planning, investment strategies, risk management, and other financial matters.

Overall, banks play a crucial role in the modern age by providing a wide range of financial services that are essential for the functioning of the economy and the financial well-being of individuals and businesses.