the shahada.
One sentence is the whole doorway. Here is what you say, what it means, and what happens after.
أَشْهَدُ أَنْ لَا إِلَٰهَ إِلَّا الله، وَأَشْهَدُ أَنَّ مُحَمَّدًا رَسُولُ الله
Ash-hadu an la ilaha illa Allah, wa ash-hadu anna Muhammadan rasulu Allah.
“I bear witness that there is no god but God, and I bear witness that Muhammad is the messenger of God.”
1 Say it with sincerity and understanding; that is the entire condition. The moment you say it meaning it, you are Muslim.
2 Witnesses are optional. Having them is lovely for celebration and community, but the shahada said alone, between you and God, is fully valid.
3 Everything before it is wiped clean. Your record starts over; that is an explicit textual promise, not a metaphor.
There is no race. Some people read this page for months before saying the sentence; some say it today. Both arrive.