Shulchan Arukh, Orach Chayim Siman 435
Can copy this into an AI, or connect the whole library to your assistant. For deeper learning, you can directly use the original seforim, sites, and apps.
לא בדק בליל י"ד יבדוק ביום י"ד באיזו שעה שיזכור מהיום לא בדק כל יום י"ד יבדוק בתוך הפסח לא בדק בתוך הפסח יבדוק לאחר הפסח כדי שלא יכשל בחמץ שעבר עליו הפסח שהוא אסור בהנאה ועל הבדיק' שלאחר הפסח לא יברך:
The law regarding one who did not check on the night of the 14th. Containing 1 paragraphs: If one did not check on the night of the 14th, they should check on the 14th day at whatever time they remember. If they did not check the entire 14th day, they should check during Passover. If they did not check during Passover, they should check after Passover so as not to fail regarding leavened bread that passed over it during Passover, which is forbidden for benefit. And concerning the checking after Passover, one should not recite a blessing.