A useful manufacturing quotation starts with controlled project data. Missing quantities, stackup information, assembly drawings, or test expectations force a supplier to quote with assumptions, which makes later changes more likely.
PCB fabrication information
Provide Gerber RS-274X or ODB++, drill files, board outline, layer count, material family, finished thickness, copper weight, solder mask and legend colors, surface finish, controlled impedance, panelization needs, and the required quantity. Identify blind or buried vias, edge plating, castellations, countersinks, press-fit holes, and other special processes.
Assembly and sourcing information
Include the BOM with manufacturer part numbers, approved alternates, quantities, packaging, and any customer-supplied materials. Add centroid data, assembly drawings, polarity references, stencil requirements, programming files, firmware version, serial-number rules, labels, and conformal-coating or cleaning requirements.
Inspection, test, and delivery
Define workmanship criteria, SPI or AOI expectations, X-ray targets, ICT coverage, functional test procedures, fixtures, pass/fail limits, and required reports. State prototype and production quantities separately, together with delivery destination, packaging, and target dates.
The clearer the package, the easier it is to compare price, lead time, risk, and engineering support across suppliers.