do you mean collect the addresses from the mail in the folder? That would use the address crawler add-on you can download it here https://freeshell.de//~kaosmos/index-en.html#eac

In order to install a downloaded extension, please do the following:

1. Click the menu button and choose Add-ons.
2. Drag your downloaded XPI file to the Add-ons Manager tab and drop it.

or

1. Click the menu button and choose Add-ons.
2. Click the gear icon at the top-right corner to the left of the search box and select Install Add-on From File…
3. Locate the XPI file you downloaded and click Open.

You may need to restart Thunderbird when prompted. For more detailed instructions and information about installing add-ons, see Installing an Add-on in Thunderbird.

i installed that ad on but i do not know how to move 650 email addresses from a folder into the address book. how can i do that?

If I recall correctly it creates a right click context menu entry. So you click a folder, right click and choose to crawl the folder for addresses.

Matt is very smart and helpful. Thanks a lot.