﴿ أَمْ يَقُولُونَ ٱفْتَرَىٰهُ ۖ قُلْ فَأْتُوا۟ بِسُورَةٍۢ مِّثْلِهِۦ وَٱدْعُوا۟ مَنِ ٱسْتَطَعْتُم مِّن دُونِ ٱللَّهِ إِن كُنتُمْ صَٰدِقِينَ ﴾

“And yet, they [who are bent on denying the truth] assert, "[Muhammad] has invented it!" Say [unto them]: "Produce, then, a surah of similar merit; and [to this end] call to your aid whomever you can, other than God, if what you say is true!”

Please check ayah 10:40 for complete tafsir.