Explained briefly, since Australia’s false news media is not reporting on this, Texas and many other states are suing the states of Georgia, Michigan, Pennsylvania and Wisconsin in the US Supreme Court. The argument is that these four states violated the US constitution in passing new election laws to allow mail-in voting and other changes to their election process.
The Constitution of the United States says that only state legislators and not state governors, attorney generals, or secretary of states can change how elections are processed. The case has been docketed by SCOTUS, and will be thus be heard.