In newer versions of TYPO3, user settings are located in the top navigation bar, on the right-hand side. Clicking the user name, will expand a menu, where you can select 'User settings'. In older version you can fins the user settings in the control panel.
Bellow the tab 'Personal data', you can add you name (1) and e-mail address (2). There are functionalities in TYPO3 that use your email address, for example to notify you whenever someone logs in with your account (3). NOTE that you will also receive an email when you login yourself, but it is a great feauture to use if you are on vacation, to keep track of any accout activities.
A profile image (4) can be added, if one wishes and the interface language can be changed (5), if a language pack is installed (default is English, please speak to your supplier to add more languages).
The information on the 'Password'-tab, can look a bit different depenting on TYPO3 vesion. In some cases you will need to fill out your current password (1), the new password (2) and then repeat the new password (3). In other versions, you will only find the field for new password and a repeating field.
The 'Startup'-tab allows you to set which module in the control panel, you wish to open up in, when you log on to TYPO3 backend. For example, if you work a lot with the news module or product manager, it might be a good idea to have the 'List' module set as a startup.
The tab 'Edit & Advanced functions' a lot of settings, that allow you to adjust and personalize your account.