Main feeder or sub-feed?
Commercial or residential?
How far?

Your question is way too vague to answer accurately.

Hello?

We are waiting to hear back from you.

I need to run 100' from main breaker to shop what size wire would you recommend for air compressor welder and lights

Kenndb,
Based on the minimal information provided, I would guess the conductor size to be #2 awg.
Now to get a more definitive answer:
What voltage?
Single phase or three phase?
What is the horsepower of the air compressor? Rated voltage and phase?
What is the rated voltage, phase and kW demand of the welder?
How many lights? How many lamps in each fixture?
(The air compressor and welder will have the above information on a nameplate attached to the equipment)
If you can provide the above information one of us can do much better than guess!