Palau and the Marshall Islands are signatory states to the Hague Apostille Convention.
To prove the authenticity of the public documents issued in these countries, you can apply for an apostille to be issued at the respective local offices.
For Palau please check here: https://www.hcch.net/de/states/authorities/details3/?aid=1132
For the Marshall Islands please check here: https://www.hcch.net/de/states/authorities/details3/?aid=373
The German Embassy can legalize public documents from the Federated States of Micronesia. In individual cases, please contact the embassy by email: firstname.lastname@example.org.