Some community topos are done by individual climbers and some are maintained by a team.
When topos are made by individuals, anyone can add information except access information. When it comes to editing the information, only the climber who has added the information can edit it.
When a crag is maintained by a team this is indicated below the name of the place. E.g. Climbing Crag, in the area of Climbers Paradise. Mainted by team TEAM X.
In this case only members of the team can make edits or additions to the topos. If you wish to contribute, you can ask to join the team. After that you have the rights to do edits even to the information other people have added.