Is it possible to extend the stay period beyond 15 days if needed while in China?

If foreign nationals intend to stay in China for a period exceeding 15 days, they should apply for a visa that aligns with the purpose of their visit at Chinese embassies or consulates abroad in advance. If, after entering China under the visa-free policy, they have a valid and justifiable reason to continue their stay, they should apply for a stay or residence permit at the local public security authority's exit and entry administration office.