Be transparent – Your client wants to know where their money is going, so don't hide or be too general with line items on your invoices, and be prepared to show receipts. Otherwise, they'll wonder if you're padding the bill. Be specific. For example, instead of listing "materials" as a single expense, list each one on its own line, such as: paint, nails, plywood, etc.
Terms (or Payment Terms): Invoice terms depend on common practices of your industry, your relationship with the customer, and your cash flow needs. For example, “Net 30” means that the invoice is due 30 days after the Invoice Date. Be mindful some businesses may pay later than the stated due date, so you may want to include a buffer to keep your business free from a cash flow gap.