Filters as well as signature settings get changed in the settings of your mailbox:
Intranet & Backoffice > Webmail > Settings > Mailbox Settings > Filter

The signature as well as filter settings get changed in the settings of your mailbox:
Intranet & Backoffice > Webmail > Settings > Mailbox Settings > Signature

Webmail is a system for the management of emails. Emails can be written, sent, saved, forwared, etc. - in fact everything an email system provides. Webmail contains mailboxes, folders, address book, filters, signature, GNU privacy guard, search mode, etc.

The advantage of Webmail: it is web based. That means that no special client is necessary. Emails can be downloaded from any computer which is connected to the Internet, using a browser and a login.

The import into the address book can be accomplished with any *.csv-file (comma separated values). Hence you can import data from any email program which supports the export of *.csv-files. This is possible with almost any current email program (Outlook, Thunderbird, ...).

Please check the priority of your filters: Filters with a higher priority get accomplished first. Hence, if one filter with a higher priority applies already, possibly filters with a lower priority don't work any more.