There are three sets of folders: global, email address, and local folders. I just installed eMClient, and these three folders seem to all have the same content. Thus two of the folders appear to be redundant. Please explain what each is and why it exists, and what is the purpose of having these three folders.
The global folders are useful when you use eM Client with more than one email account. They show an aggregated view from all email accounts. You can turn this feature off completely if you use eM Client with single account, the option for that is “Show Global folders” in Tools -> Settings.
The local folders are used for POP3 accounts that are not setup to use different folder set (eg. the “email address” folder set you mention). They also contain the Outbox folder that contains messages that are about to be sent. You can hide the Local Folders with the option is “Show Local folders” in Tools -> Settings, but beware that this will also hide the Outbox folder.
Finally the “email address” set of folders is there for each IMAP account (note that services like Gmail use IMAP) or POP3 account (if the “use separate folder tree” option was checked when creating the account).