Equity investment of listed companies, can you invest in this listed company? What does it mean if you can invest and hold it?

Strictly speaking, investing in listed companies means buying shares of listed companies. Because the shares of listed companies have been securitized, there is no other way to enter unless any part of this company is not loaded into listed companies.

Generally speaking, equity investment does not invest in securities, because equity investment means that companies invest in unlisted enterprises in the form of equity to obtain the return of equity appreciation.

Does the listed company invest its own equity, or does it set up a leather bag company, and then the listed company wholly owns the leather bag company?

It is definitely not good for listed companies to buy directly by themselves. It should be possible to operate by becoming a shell company and then cross-holding with other companies through stock exchange. But it's best to consult a lawyer and an accountant. If the structure is not good, it will be investigated.