When you check oil level there should be 2 holes, lines or a crosshatch area on the dipstick. Proper oil level will be between those two holes, lines or in the crosshatch area. If its below then add oil until its in proper spot.

Also if you can gain access to a lift or just have to jack it up and put it on jack stands, get yourself a very bright light ( shop light, w/e) and start from the lowest point of the engine bay. When you find a wet spot or drip follow it to its highest sopt and you should find your leak point.

If there is NO sign of an external leak then check the PCV valve for heavy oil contamination. If its soaked replace it. The PCV valve could be faulty. If its not then check it for proper operation by shaking it like a salt shaker. If its rattles then its "OK". Put it back.

Check your exhaust color now:
White = Coolant consumption.
Black = Rich Air/Fuel mixture.
Blueish = Oil consumption.
Grey = Normal

If its Blueish then:
Next pull spark plugs and look for contamination there. If there is then you have most likely found your leak. Its internal most likely from there. If this is the case it can be a few things. If its got some serious high milage it could simply be worn out rings. Or it could be worn/bent valves/valve guides.

Test the car in various conditions.

Cold startup: If the car puffs blueish smoke and then goes away after a few minutes or the car has reached operational temperatures. Then its most likely oil that has puddled up behind the valve and is then burning off after startup. If the burn off stops after the car warms up then its because the parts have expanded enough to stop the leak, but eventually the wear will cause it to leak during all conditons.

Hot startup: The valve & guides have expanded so much that oil is bypassing both parts. When the car cools down it seals the leak.

During all running conditions: It may be extreamly worn valves and guides or the piston rings are worn badly.

If its the rings, its gonna be a teardown process. You should have the block honed to return its "round" factor. Replace the rings. At this point you should also inspect the head for any future possibilities.