Under US law organisations are required to get consent from consumers before sending certain documents electronically. For example, where a statute or regulation requires that certain documents relating to a transaction be provided in writing, these documents cannot be provided to an individual electronically unless the organisation obtains a specific consent from the consumer.
A Consumer Disclosure Agreement is generally necessary where a business is sending documents electronically to consumers where there is a cross national or state border element to the transaction. However, a lot of states also require a consumer to give prior consent to signing electronically for transactions within that state. The law varies state by state so you should get independent legal advice on whether the law imposes a requirement for you to obtain a Consumer Disclosure Agreement.