The battery Isn't taking a charge

@shahinsultana you have not told us how old the battery is. If it is one of the original batterie, then you want to start by replacing it. It stands to reason that it has degraded to the point of no longer holding a charge.

If this is a new (relative) battery then you do want to check your charger to make sure it provides the proper voltage as well as the charging cable. Make sure there is no corrosion, bend pins or any other physical damage.

The same with your charging port. Make sure it is clean, does not show an corrosion or bend pins. You can clean with a soft nylon brush and a few puffs of compressed air (air-in -a can)

For anything further you want to check page 23 of this Nokia 3310 3330 Repair Hints V3 0 It will tell you which components to check etc. This documentNokia 3310 Schematics Layout shows you where those components are located on the circuit board.