I have been having problems with the toilet bubbling when the washer or tub drains.The kitchen sink also fills when the washer drains.Can someone please help! The tub also drains slow.

You have a dandy clog in the sewer line somewhere. Try plunging the sink and toilet to unseat this clog. If that doesn't work you might try a plumbing snake and see if that helps. Try and figure out the first drain on the line and snake that drain.

Thank you Twinkle

Plunging will not work in this scenario. The clog is not in the washer or the tubs, its downstream past the toilet. A toilet auger will reach about 4' so its worth a try but a longer 1/2" rod may be need starting at the nearest dry access or clean out. You can also rod down your vent stack from the roof.