A good share of disposal call-outs turn out to be a two-minute fix, so it is worth trying before you ring anyone.
Start here
If it hums but will not turn, the motor is fine and something is jammed. Switch off the power at the wall, use the small hex key that came with the unit to free the flywheel underneath, then press the reset button on the bottom. If it is silent, the reset alone often sorts it.
Builder-grade units in serious kitchens
Homes here often have kitchens designed for proper cooking and entertaining, fitted with whatever disposal the builder specified. If yours jams on ordinary food waste rather than something unusual, the unit is underpowered rather than broken — and upgrading solves it permanently.
When it really is finished
Water coming from the body of the unit rather than the connections means it has rusted through and cannot be repaired. Repeated tripping after a reset means the motor is going.
What it does not deal with
Cooking oil and fat. They go down warm and set further along the pipe, and on the long drain runs in these houses that is the usual reason a kitchen drain starts blocking.