How do I set sender information?

Sender information can be set in Settings → Basics. Here's what this looks like:

By default the:

• "Username" will be the "From address".
• "Author name" will be the "From" name displayed in the email client.
• "Email address" will be the default "reply-to" address.

For example, using the settings in the screenshot above, a newsletter header would look like this:

from:	Paul L'Astname <jenna@buttondown.email>
reply-to:	paul@buttondown.email
mailing list:	jenna@buttondown.email

If Tracked replies are enabled, the reply-to address will instead be in the following format: replies+BIG-LONG-ID-NUMBER@buttondown.email

from:	Paul L'Astname <jenna@buttondown.email>
reply-to:	replies+1234-5678-9101-1121@buttondown.email
mailing list:	jenna@buttondown.email

While there's no real "best" practice for setting a Author name, we recommend setting it to something you readers recognize and expect. That could be your name, or the name of your business or organization.

To frame this differently: Your Author name is an opportunity to drive engagement with your newsletter. The best way to do this is by preventing reader confusion.