A notice of termination is signed only by the party giving the notice of termination. You can sign an acknowledgement of receipt. This has to be a separate letter in which you sign that you received the termination on a certain day.

Attention: If your employer wants you to sign a termination, then perhaps this is a termination in your name or a termination agreement! If you sign these documents, it is very difficult to fight the termination afterwards. The problems that a termination agreement can entail can be found here.

As a rule, you do not have to sign anything immediately. You can always ask to read the text in peace at home. Then get advice from your trade union or a Fair Integration advice centre!