Take a taxi from the official line-up. Fixed price 50 euros right bank, 55 euros left bank. Ignore any attempt to offer rides from strays in the terminal lobby. There is rapid transit via the RER suburban rail, hooking into the Metro subway system. It's cheaper and possibly just as fast, but more stressful. Research here for rapid transit:
https://www.ratp.fr/en
Hint: "Customs" is declaring anything special you are carrying. Usually there is a green door for "nothing to declare" that you simply walk through. A spot check is always a possibility but uncommon. Immigration and border control take the time and there is no way to estimate, even day by day, how long it will take. Same can be said for the efficiency of the luggage retrieval. Getting out of CdG in anything under an hour could be considered speedy.
To orient yourself at CdG, search for a site called Easy Charles de Gaulle.