Asking for a deposit up front

Any invoice can carry a requested deposit amount — a plain dollar field in the invoice editor, separate from simply recording whatever payment happens to arrive.

While the deposit isn't fully covered, the public invoice page leads with "Deposit due now" instead of the full balance, and both Stripe Checkout and PayPal target exactly that shortfall.

Once the deposit is satisfied, the same buttons automatically switch to charging the remaining balance. There's no separate deposit checkout flow to configure.