How can I upload a folder using API call?
While the Dropbox API doesn't offer a way to upload an entire folder including its contents at once, you can create a folder using /2/files/create_folder_v2, and as Здравко noted, you can upload files using /2/files/upload.
https://www.dropbox.com/developers/documentation/http/documentation#files-upload
Folder creation can be skipped. The folder will be created on first file upload if missing. 😉