Of course, if you use intuit merchant services and allow customers to pay online the invoice they receive by email will not only tell them they can pay online but will include the link. (in the email, not the body of the invoice)

Beware, the payment can go through, in a day or two, the payment can be declined (basically an NSF).  At that point you must manually create journal entries to reverse the transaction, recreate a new invoice to resend with a new payment link and then create a credit memo to clear out the first invoice linked to the declined payment.  Someone should create a better process for this.  If you have 2 or 3 declined payments in a month, it can get to be a hassle.