Investors can only purchase and redeem open-end funds on the fund open day. The opening day of the fund is generally the trading day of the securities market. On the fund open day, investors can go through a series of procedures such as subscription, redemption, change registration, fund conversion, account cancellation, loss reporting and transfer. It should be noted that applications accepted after 3 pm can only be included in the next open day. There are many channels for investors to buy and sell funds, such as banks, securities companies, fund companies, third-party fund institutions, and also through the telephone and the Internet. It should be noted that according to the principle of fund trading, funds purchased by investors can only be redeemed there. If you want to change the trading channel halfway, you need to go through the formalities of transferring custody. Therefore, it is very important to choose the right channel when purchasing funds.