Kmail's settings window gives you a number of ways to customize Kmail to your needs.
The settings in the Identity tab are fairly straightforward. The Name and Organization fields should contain the appropriate information if you want this information to be automatically included in the headers of any message that you send. The Email Address and the Reply-to Address field should contain your email address. The Signature File field contains the location of your signature file. You can skip setting the signature file if you do not have one. If you do this, make sure that you also uncheck Automatically Append Signature in the Composer tab.
The Network tab contains the settings that tell Kmail how to send and receive your email. Many of these settings can vary greatly depending on the setup of your system and on the kind of network that your mail server is located. If you do not know what setting to pick or what to put in a field, consult your Internet Service Provider (ISP) or System Administrator.
The Sending Mail section provides two options for sending mail: sendmail and SMTP. Sendmail has a reputation of being difficult to set up, so if you do not already have a working sendmail configuration, choose SMTP and fill in the Server field with the name and domain of your mail server. You will probably not need to change the Port setting.
To set up an account so you can receive mail, press the Add... button in the Incoming Mail section. You will then be prompted for the type of account. Most users should select POP3. (IMAP accounts are not supported) After pressing OK you will be presented with the Configure Account window. First, fill in the Name field to name your account. Login, Password, and Host should be filled in with the appropriate information from your ISP or System Administrator. Again, you should not need to change the Port setting. Select Delete mail from server if you don't want to leave your mail on the server. Finally, you can set the default box to received your new messages.
This tab lets you change the type and size of the display fonts in the Main and Composer windows.
The Phrases section lets you define the automatically generated lines added to message replies, forwarded messages, and quoted text. There are special %-denoted characters that will insert certain values. These are shown at the top of the Phrases section: %D to insert the date, %S to insert the subject, %F to insert the sender, and %% to insert a percent sign. The Indentation field contains the character that will denote quoted text.
The Appearance section lets you control various options for your messages. Automatically Append Signature and Automatically Sign Messages let you toggle whether to automatically include your signature and PGP signature in all of your messages by default. Word Wrap At Column lets you turn word wrapping on and off in the Composer window and lets you set the column at which words will be wrapped.
The When Sending Mail section lets you customize how and when messages are sent.
The Default Sending options lets you define what happens when a message is sent. If send now is selected, the message is sent to the mail server immediately, while if send later is selected, the message is queued in the outbox to be sent later with the File | Send Queued command or automatically when you check your mail, depending on the settings in the Misc tab.
The Send messages options let you select how your message will be encoded when it is sent. Allow 8 bits means that Kmail will send your message in 8 bit ASCII, which means that all special characters such as accented letters will be sent as-is. If MIME-compliant (Quoted-printable) is selected, then special characters will be encoded using standard MIME encodings, which may be more portable to other mailing systems than 8-bit ASCII.
The trash folder is cleared of messages when you quit Kmail if this option is selected.
All messages queued in the outbox folder will be sent whenever you check your mail.
If enabled, kmail will automatically send a receipt to the sender of the message when it receives the message and/or you read it. Currently (KMail 1.0.24), only receive confirmation is implemented.
This tab controls the PGP features. At a minimum, you must fill in the PGP identity field so that Kmail can properly interface with PGP or GNU Privacy Guard.