If you archive a constituent all the information you have about them is retained but they are put into an inactive state - this makes it easy to exclude them from lists & mailings, note that payments will be not be collected for recurring payment instructions belonging to archived constituents.
The delete function is available to Administrators only.
To archive a constituent:
Locate the constituent you want to archive. Click on Manage and then Archive Constituent.
Next enter the Archive Date and Archive Reason for archive and then click on Archive
When you retrieve an archived constituent a banner is displayed at the top of the constituent's record indicating that they are archived.
Searching for Archived constituents:
Archived constituents are returned in the search results unless you search only for active constituents.
To search specifically for archived constituents, type in your search keyword, then click on Search. Next, to refine the search results for only the archived variant, click the Status radio button next to Inactive
To Delete a Constituent:
If you delete a constituent then all information about that constituent is permanently deleted - there is no way of getting it back.
Locate the constituent you want to delete. Click on Manage and then Delete Constituent.
Donorfy will ask if you are sure you wish to delete the constituent, click on Yes (or no if you clicked by accident or no longer wish to delete).
The constituent will now be deleted.
Bulk deleting and archiving:
Archiving All Constituents on a List
No mention of the authority level to delete a constituent. This should be part of Data Management but it appears you need to be an administrator which is dangerous.