There is a myriad of clothing companies on the internet. A lot of them are included in directories and lists. You'll need to look up terms like apparel, garment fabrics, clothing, and so on.
You may also wish to put your requirements in an online forum and then see the companies that others have recommended. You can find the best manufacturer in London, UK online.
What should you look for? – When looking for a supplier, first determine all of the details you require. Do you require silkscreening? Do you need it for t-shirts, children's clothing, fleece or suits?
These kinds of details will help you identify the kind of manufacturer. There are companies in the clothing industry that specialize in silk screening and t-shirts.
What are your costs? – Choosing a manufacturer from the United States will of course cost more than using a foreign manufacturer. However, foreign companies typically have high minimum order requirements and won't work on a small quantity.
What do you need to know about posting your job online? – Another way to locate an apparel maker is to put your post on a job board for companies and then let them offer to bid on the job.
Be sure to eliminate any manufacturers with negative reviews or feedback that is negative. At the beginning with your search, you should select a company that has positive reviews or feedback.
Be sure to evaluate the various bids for your job before deciding on who you want to collaborate with.