QB Issue Resolution:

It really depends on the time between contract and delivery   a couple of days just invoice them, other wise

I would create an estimate

convert that estimate to an invoice when you ship or deliver

Resolution for Issue 'What is the preferred way to record a sale in QB after our customer has signed a contract but before our firm has delivered the merchandise?' available: Yes (Solved).
Source: Intuit Community forum.

What is the preferred way to record a sale in QB after our customer has signed a contract but before our firm has delivered the merchandise?: this issue or error code is a known issue in Quickbooks Online (QBO) and/or Quickbooks. Support for this issue is available either by self-service or paid support options. Experts are available to resolve your Quickbooks issue to ensure minimal downtime and continue running your business. First try to resolve the issue yourself by looking for a resolution described below. If it is a complex issue or you are unable to solve the issue, you may contact us by clicking here or by using other support options.

Support for contract and delivery
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Error Recovery for contract and delivery [Canada]
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