Introduction:

The passive voice replaces the subject with the complement or object.
It is frequently used in scientific journals to keep objectivity.
Consider:
I am watching the movie.
The movie is being watched by me.

Structure:

Present simple subject + is/are + verb (past participle)
Past simple subject + was/were + verb (past participle)
Future with will subject + will + be verb (past participle)

Present (simple, continuous, and perfect)

The participants see the presentation. (active voice) -The presentation is seen by the participants. (passive voice)
The participants are seeing the presentation. (active voice) -The presentation is being seen by the participants. (passive voice)
The participants have seen the presentation. (active voice) -The presentation has been seen by the participants. (passive voice)

Past (simple, continuous, and perfect)

The participants saw the presentation. (active voice) -The presentation was seen by the participants. (passive voice)
The participants were seeing the presentation. (active voice) - The presentation was being seen by the participants. (passive voice)
The participants had seen the presentation. (active voice) - The presentation had been seen by the participants. (passive voice)

Future (simple, continuous, and perfect)

The participants will see the presentation. (active voice) -The presentation will be seen by the participants. (passive voice)
The participants will be seeing the presentation. (active voice) - The presentation will be being seeing by the participants. (passive voice)
The participants will have been seen by the presentation. (active voice) -The presentation will have been seen by the participants. (passive voice)