A lot of cheap USB chargers, and USB ports on PCs will only go to 500mA which takes forever to charge a decent tablet. If you can get 1 or 2A then better, though a car charger will struggle.
Some need more voltage. My Dell tablet will charge on regular USB 5V 1 or 2A but takes all day to do it, but the supplied charger is 19.5V 24w but 1.2A yet charges much faster than regular USB (Dell have special support to handle the higher voltage charger).
Ps you can get USB fast charge dongles that short the data connection which for some chargers and on PC ports will convince the device that it’s not data connected, only power and might draw more current than the stock 500mA.