Family Historian User Group

How can I add witness events like Census to the Individual Summary Report?

The short answer is you can't.
Only the primary Census Event can be included in the majority of reports.
The Fact Witnesses of any fact, including Census Events can ONLY be included in Narrative Reports.
That is one reason why how_to:recording_census_records|> Recording from a Census Record advises against using them.

With some customising it is possible to list Fact Witnesses at the top of an Individual Summary Report but they certainly can't be included in the chronological list of Individual Events and Attributes below.

Witness events will be included on the Individual Summary Report in V7.