just send a mail to your @Handle and every char you got has access to open it i did this in game earlier no problems at all.
To be more specific, you start the email from the mail station as usual. There are 5 slots at the bottom of the mail to put items into. Drag items into the slots. Send as usual. Go to the character you sent mail to (if its your own alt), go to the mail station, chekc the mail. When you open up the mail, you will see take items highlighted in the mail. Click it. Done!
You can not claim items in space, only from the mail stations.