If club members are asking about automatic deposits instead of giving the treasurer a check:

The club should check with the brokerage if they have an address that payments can be mailed to. Many online banking services allow payments to individuals or manually entered addresses.
For example, Fidelity allows payments sent in to:
Online Bill Pay: Fidelity Investments; [FIDELITY Account number]
Address P.O. Box 777001
Cincinnati OH 45277
Phone 800-544-6666.

In these cases, members should add an agreed on number of cents to their payment; brokerages may not show the name of the member who sent the payment in, so it's important to make sure the treasurer knows who sent in a payment. We call this the 'cents method' and it would look something like this:

• John Doe: 100.01
• Jane Doe: 100.02
• Joe Darling: 100.03
• Mary Darling: 100.04

As long as each member puts their agreed on number of cents at the end of their payment, the treasurer can tell who each payment should be applied to.