I would decide on the industry and research it so you can have informed conversation with the manufacturers you reach out to

What type of manufacturing and in what country?

Rad Sourcing, We help set up ethical manufacturing overseas and manage the production process from start to finish; Including design, prototyping/sampling, production, quality assurance, and freight/logistics

https://www.radsourcing.com/

What are your desired quantities and target price point? If you are setting up manufacturing domestically it will be much more expensive per unit than overseas on the other hand you get the brand cache of being USA Made. Generally, if you produce domestically apparel manufacturers here are going to handle cut and sew and you will have to source or provide the materials or expand your manufacturers scope of work and have them do it for you for a fee. Overseas is costs are generally inclusive of both the labor (C&S) and materials.