An invitation to bid will include information describing the goods or services required in sufficient detail to enable the bidder to prepare an accurate tender that is in a
prescribed format so that it is easy to compare with other bidders.
An invitation to bid might include:
Letter of invitation to bid.
Form of bid.
Preliminaries (including pre-construction information and site waste management plan).
Form of contract, contract conditions and amendments.
Bid pricing document (or form of contract sum analysis on design and build projects)
Drawing schedule.
Design drawings.
Prescriptive or performance specifications (on public projects, bid documentation may
include an output-based specification rather than prescriptive or performance
specifications and drawings).
Instructions to bidders explaining the bid process.
The timescale for the bid process (including the address and time for the return of bids).
An explanation of how questions will be dealt with.
The evaluation process and any evaluation criteria.
The submission required in response to the invitation to bid.
Policy in relation to alternative or non-compliant bids. (Design Building Wicki)
based on my understanding, these two words are describing the same thing. If they are different, construction contract documents refer to the things prepared by the designer before the construction and project's contract documents refer to something may add to the original document during the construction.
But almost tests won't let you compare these two, instead, there is another one project manual which includes bidding things and other things. and drawings typically in a separate CD with project manual "book" .