WorldPosta is a web-based email system (and also supports Outlook, Thunderbird, and other mail clients). Your email message, address book, calendar items, and other mail information is stored on our servers and your computer too.
Attachment and links sent along with email are nor a thread to your systems if you don’t download or click on them.
If you choose to open or download an attachment to your system, your computer doesn’t get affected as WorldPosta automatically scans all the inbound and the outbound attachment for viruses and harmful attachment using multiple levels of security, it detects these kinds of files and stops them from reaching your email.
It is generally recommended that you do not download attachments or other files, or click emailed links from a source that you do not know and trust and that you install up-to-date anti-virus software on your computer, and download the latest virus definitions frequently.
For further security information: https://www.worldposta.com/data-center-amazon-aws-google-cloud/