What are you sending?

Estimate

A professional guess.

The number can move if the job moves. Not a promise. Send this when you have not seen everything yet.

Quote

A firm price.

Defined job, one number, holds as dated. They can seal on the same link — a name, a PO, an agreement. Send this when you can stand in it.

Estimate, then quote

Ballpark first.

Send an estimate. They talk. You revise this same page. Hold a quote when you can both stand in the number.