The process for fast fashion is very similar to regular fashion & apparel products except for the fact that after the initial set-up : a large part of recurring "drops" are Automated!
If you are not sure what does a brand need to provide before you are ready for manufacturing, we suggest you read the hyperlinked answer.
In order for your brand to be ready for manufacturing, you would need those information. This happens via product development process.
There are several independent service providers for each stage of product development. Hula Global does not endorses or recommends anyone in particular. You are advised to do your research and evaluate each service provider on your own.
Additionally, we also provide product development services. You can find more details about those services under the resource section of our website - Development Charges.
We have a dedicated section of FAQs on Product Development. If you are looking for product development support, we recommend that you definite read this section.
Once your product development is complete and fabrics approved, as long as you keep the same fabric (in terms of GSM and composition) and keep the same core design - you don't have to do product development again for the next collection.