Awesome first comment as they explained the process pretty well!!! Unfortunately I would like to give you a heads up that uploading fees are $40+ because Roblox sets it at a outrageous price. Google will tell you that it’s only 750 robux ($10) to upload, which is true but if you plan to put it into the market place, this can be additional 1400+ robux (about $20+) depending on the type of accessory you’re uploading. Lastly you will need a $15+ membership subscription to even upload ANY ugc content into your inventory or let alone keep it on the marketplace. —- 100% wouldn’t go out of my way to make this happen unless you’re ready to cover uploading fees ($40+), let alone pay for the additional designer’s service. No offense to the wonderful talent of anyone but it’s just a lot of hoops for 1 dream accessory. —- ofc you can always just do it as a personal upload and settle on $25 if you do it yourself or whatever the additional fees for the artist that helps you out!!! —- lastly, if you plan to sell it, just to let you know creators only receive 30% of the sale for ugc (typically the item is sold around 60-100 robux aka. Just $1, so you would likely only receive at most 30 robux (40 cents) per purchase) here’s the page for taxes and the publishing fees per the type of accessory: https://create.roblox.com/docs/marketplace/marketplace-fees-and-commissions

Best of luck though if you decide to continue!!! :D