Direct Mail is physical marketing mail sent directly to prospective customers via postal services. This can include letters, brochures, catalogues, etc. and, unlike email content, Direct Mail does not require permission from the customer.
However, while that does mean you can legally reach a wider audience, Direct Mail is generally less likely to result in engagements and conversions. Additionally, the costs are higher as they demand resources.
With that said, Direct Mail can be an effective method for small, local businesses reaching nearby consumers as the content is much more difficult to ignore. The personal approach of actually going to consumers’ doorsteps also taps into the sense of local community.