@cloudguy I'm more or less certain that NLS (oNLine System) from Doug Engelbart's ARC (Augmentation Research Center) group at SRI (Stanford Research Institute) already demonstrated copying and pasting of text in the 1968 "Mother of All Demos".
However, it is true, if perhaps lesser known, that Xerox's PARC had a cross-licensing arrangement with SRI and SAIL (Stanford Artificial Intelligence Lab).
Lamentably, due to Hollywood BS such as Pirates of Silicon Valley, many (almost all?) in pop culture erroneously attribute inventions to PARC which were previously invented under Engelbart's team and elsewhere.
For example even earlier, Ivan Sutherland's Sketchpad (movie clip below from 1962, doctoral thesis completed in 1963) had copying and pasting graphical objects and object inheritance, a clip here narrated by Alan Kay (who was a student of Sutherland and also later worked at PARC):