You can use labels to categorize your messages in Gmail. Labels such as "Inbox", "Starred" and "Important", etc. appear on the left and you can decide which one to show or hide.
Step 1: Login your Gmail account (please refer here to open one if you do not have an account yet);
Step 2: In the Gmail account, click the "Setting" button from the right-top corner;
Step 3: Click the "Settings" command from the drop-down list;
Step 4: Click the "Labels" tab in the settings menu;
Step 5: Check the labels you want to show or hide;
Step 6: If you use Outlook, check "Show in IMAP" to show the label in Outlook;
Step 7: You can create, edit or remove a label at the bottom of the page.