Finishing your involvement in a project creates a final deliverable: continuity. Give the receiving person enough information to operate, maintain or responsibly close the work.
Identify the authoritative files, current status, unresolved decisions and access arrangements that need an authorised transfer. Handle credentials and private information through the appropriate secure process.
Test the handover's usefulness
For a fictional reporting setup, ask the receiving owner to complete one example, locate its source and explain how an error would be corrected. Record questions still requiring an answer.
Distinguish accepted deliverables from work merely sent for review. Clarify any support arrangement and its limits so the recipient can plan realistically after your involvement ends.
Preserve a proportionate record of what was transferred and acknowledged. The next person should not need to reverse-engineer your intentions from a collection of final-final filenames. A useful departure respects both the work already done and the person who will carry its consequences into the next operating period.