Study the information about phrasal verbs with on/off.
1. We use on/off for lights, machines

The light is on.

Turn the light on/off.

Shall we leave the lights on or turn them off?

2. On and off are used when talking about events.

Go on = happen

Call something off = cancel it

Put something off, put off doing something = delay it
The open concert had to be called off because of the weather.
3. Use on or off, when you talk about clothes.

Put on glasses, clothes, make-up

Put on weight = get heavier
Try on = see if it is good or not
Take off clothes, glasses.
It was warm, so I took off my jacket.
4. Off = away from a person or place.
Be off (to a place)

Walk off, run off, drive off, ride off, go off

Set off = start a journey

Take off = leave the ground (for planes)

See smb. off = go with them to the airport/station to say goodbye

We set off very early to avoid the traffic.

Next week I am off to Paris.
Raymond Murphy. English Grammar in Use- Cambridge: CUP, 379p.