Dear friend,
A force is something which causes accelaration to an object having mass with reference to a non accelerated reference point.
For example when we drop a ball from our hand, the force acted on the ball is gravity with an acceleration a= 10m/s² with reference to the hand used to drop the ball.
Another example is when we push a swing in a park, it moves with some acceleration given by the force of the push.
Hope this helps
CHEERS