You really should hire a lawyer,a CPA and insurance adjuster at a minimum to assist with answering this question as it is very open ended. Here it an incomplete list of some of the documents and licenses, but your particular company may/probably will need to consider other licenses and documents. City/county business license, resale license, fictitious business name filing, a corporation or LLC filing with the California Secretary of State, initial incorporation or LLC documents, EDD filing, Employer Identification Number filing and on and on. If you have employees, you will need to obtain worker's compensation insurance and you should have business insurance as well. The list of what you may need is long and there are many other things your business and you should consult with an attorney about. Again, the list above is not complete, and was written to show you that there are many things to do and why it is so important to consult with a lawyer, CPA and insurance broker. There are many great lawyers who can be found on Avvo. Interview several of them and chose the one you believe will do the best job of looking after your interests. Good luck.
*Scott G. Nathan has been licensed to practice law in California since 1983. The information presented here is general in nature and is not intended, nor should it be construed as legal advice for any particular case or matter. This posting does not create any attorney-client relationship with Scott G. Nathan or my law firm. For specific advice about your particular situation, you should consult with an attorney immediately.
For the most part, I agree with my colleague. I do want to point out that much of what you need will depend on the details of your boutique, like what exactly you will be providing and if you will have employees. For example, will you be making the clothes yourself/manufacturing? Will you be purchasing wholesale and selling retail? How many people will be working for you? You may need to deal with copyrights and trademarks as well, both associated with your website and your business name. Since you don't have a physical location, you will have different needs. For some startups that have very little liability risks opt for a sole proprietorship because of the costs involved with incorporating in CA. All of this will depend on the structure of your business and various other factors. I highly recommend consulting with an attorney prior to starting your boutique.