What‘s the meaning of the “to” in “admit to”?

See a translation

@RickHe
It has no specific meaning. It’s a preposition, a particle you need to bind words together. It has clear meaning in other cases but not next to a verb like “admit”

I gave the bag TO her (here the word indicates the direction of the bag. How the bag is transferred from one person to another)

“I admit to doing that” — here it has no meaning. It is just part of the structure verb + present participle
In English and other languages, some verbs and structures “ask” for specific prepositions. The verb “admit” needs it before a present participle but not in other cases. Look at these:

I admit that I didn’t call you
I admit it
I couldn’t admit that he was right