You will get the tickets when you check in to your hotel. However you dont have to wait until official check in time. Whenever you get to
Disneyland Paris, go to your hotel You will be able to check in, get your park tickets and leave your luggage. You can then go to the parks.
Then in the afternoon or evening , depending on your plans , you go back to the hotel and collect your room keys and your luggage.
I did this on my last visit back in 2016. I got to Disneyland Paris around 12.30pm , and was in the park by 1pm.
I went back around 4pm to get my room key. I was staying at Disneyland Hotel, which is currently closed, and they arranged for my luggage to be brought to my room.
Depending on which hotel you are at, they will bring the luggage to your room or you might have to collect it yourself from the luggage store room.