How to add a file to an existing folder?
Hey @wangzezheng1991 , while it is possible to add files to existing folders, using the ipfs Object API supported by the Kubo CLI or by using IPNS, the result will be a new object with a new CID, this being due to the immutable nature of IPFS objects. You can find some good how-to examples at the following stackoverflow link.
But, at the present moment Infura does not support the Object API nor IPNS.
Hope this helps.