Schwinn Meridian Adult Tricycle not easy to turn left. Turning right is fine

This sounds like a headset issue. You first might want to try loosening the headset a little bit by first loosening the stem bolts and then the headset bolt before retightening the stem bolts. If that doesn't work, you might want to try cleaning and relubricating the headset, and checking to see if the bearings are worn out or need replacing.

Some trikes drive only one rear wheel, so that when you're turning with that wheel on the inside, it will handle differently than when you're turning with that wheel on the outside. So that might explain it. If so, that's just the nature of the trike. Have someone hold up the back of the trike while you turn the pedals to see whether one wheel turns or both.

This trike looks like it should be driving both rear wheels and letting the outside wheel freewheel through turns. If that's the case, it may be that one of the freewheels is sticky.