To delete something you have created in the admin panel you have to keep these points in mind:
If you would like to delete a campaign in the admin panel, you click on the writing in red that says 'Delete'. This is only possible if the Campaign has not received any donations or updates by the campaigner yet.
After a campaign has received a donation, the delete button will disappear and instead you will see the option to click on Donors.
To prevent a campaign that you cannot delete from showing in your Frontend page you can open the specific campaign by clicking on Edit and uncheck the box "Is active":
If you have created a purpose and would like to delete it, no problem. Only if there are already Campaigns raising funds for that Purpose you cannot delete it any more, the delete option disappears.
Move the switch to NO in the "Is active" column and the Purpose will not be available in the Frontend.
Same as with the Purposes you can delete an event /campaign type as long as there are no campaigns linked to it. In case of existing campaigns the Delete option is no longer available but you can always set it to inactive.
A new Campaigner can be deleted as long as he has no ongoing campaigns. So first, delete the campaign (as long as there are no donations it is possible) then you can click on the delete button for the campaigner.
NOTE: For campaigners the delete button does not disappear, if you try to delete a campaigner with an ongoing campaign you will generate an error. This does not have any implications, it just won't work.
If you cannot delete the campaigner any more you can disable them and lock their account.
As long as you have not tagged any campaign you can always delete a tag again.
NOTE: The delete button stays in place, whether you can or cannot delete the tag. If you try to delete a tag that features a campaign you will also get redirected to the error page. No worries, just go one page back.