An Unlinked receipt is a document or image sitting in your Receipts inbox that has not yet been converted into an expense.
Once processed, it becomes a Linked receipt, meaning it is associated with a transaction in your Expense Tracker.
The status lets you see at a glance which purchases are already accounted for in your project budget, and which receipts still need to be filed.
Read the full article: What is the difference between an "Unlinked" and a "Linked" receipt?