Uploading MCreator files to Minecraft PE/Android.

Depends. What files do you want to upload? You can't upload mcreator, you can upload mods resource packs and data packs if you have pojav launcher, and you can upload addons if you have bedrock / pe. If you want to know just how to move the file then get a file sharing app or a drive like google drive or mega. Then put the file on it and download it on your tablet. Then just upload it to the right folder and then your set.