As long as the specific circumstances are stated, the relevant units need to sign and seal, and even the host needs to sign. For example: project participation certificate.

From 2006 to 2008, Mr. XX participated in the research work of the subject "Research on the Application of Multimedia in XX Teaching" of XXX Education Society. Under the guidance of the host, he carefully collected information, actively wrote papers, and did a lot of fruitful work with the members of the research group. The topic ended successfully.

The above situation is true.

Project leader (signature): XX.

XXX unit (seal).

XXXX，xxxx。