One receipt, one path.
Your team submits the receipt, you approve from one queue, the employee is reimbursed, and the client sees it on the next invoice with the receipt attached and the markup already applied. Purchases on the client's behalf get their own lines, with sales tax where it applies.
Approve from one queue.
Every submitted expense lands in one place for whoever reviews them: the receipt, the project, the category and the submitter's note, side by side. Approve it, or send it back with a note saying what to fix. Nothing reaches a client invoice or a reimbursement without a decision here, and the queue shows exactly who is waiting on you.
Every receipt rides with the invoice.
Each invoice carries an expense report: one line per reimbursable or purchase, with the date, who paid, what it was for, the receipt image, and the markup or tax applied. Your client sees exactly what each expense line was without asking, and your bookkeeper has the receipts in the same place as the invoice.