If you meet the requirements to get into the TikTok Creator Marketplace, your invitation will be sent to your TikTok inbox. To find messages from TikTok in your inbox easier, filter 'From TikTok' under the 'Monetization' category. If you do not receive a message, it may be because you did not fit the eligibility requirements or you are already a member of the marketplace.
Still having trouble? Reach out to support in-platform for assistance.