How to prove this intellectual property right for the jointly developed technology?

If there is an agreement between the two parties, the ownership shall be decided according to the agreement. For example, it is stipulated in the agreement that all technical achievements are owned by Company A..

Take the patent right as an example, then all parties will become the same patentee.

I don't quite understand what you mean by how to prove intellectual property rights.

If it refers to the proof of the right itself, because both parties can apply for the same development, the patent certificate will have the names of all the same owners.

If you ask how to prove that the technology is jointly developed, you can prove it through development agreements, correspondence, meeting minutes and other materials.

The original answer is from the seasonal romantic ocean.