The first rule is that you need to be honest, not only as a moral imperative, but since the outcome can be severe if you are not and it is discovered.
But you don't need to volunteer information not asked for, especially if it isn't in your best interest to do so. For undergraduate misconduct the university normally handles it and closes the case. You can too, taking it as a learning experience and doing better in future. They keep internal records in the case that you repeat bad behavior, but don't normally disclose it to others - sometimes by law.
If you are asked, then you should answer honestly, but stress that it didn't become a habit and wasn't and won't be repeated. People understand that others (like themselves) aren't perfect but can learn. Few people can compete with the angels.
This, alone, shouldn't have an impact on graduate admissions in most cases, but, since decisions are made by individuals, it is impossible to predict with precision.
In an earlier version of the question you asked about admission to some top schools in the US. Your chances there are determined by lots of things, but note that the competition is very fierce at the top level. I recommend, as always, that you make a broad search for a doctoral program so that you aren't closed out completely. Note that if you are rejected by one top program you are probably(?) going to be rejected by other similar programs on the same basis. Shoot for the stars, but settle for the moon.
