Mix water, salt and sugar in a saucepan. Place over medium heat and stir until the salt and sugar dissolves. When the water boils, pour in the vinegar and after a minute turn off the heat.
Sterilize canning jars in advance with boiling water or hot steam. If you don't plan on storing for a long time, you can skip this step. In this case, store in the refrigerator once jars are filled. Arrange mustard seeds, peppercorns and coriander seeds in jars.
Fill jars with chopped vegetables or fruit pcs. Shake the jars to make pieces more compact. Don't fill the jars too tightly, typically just divide between 3 mason jars.
Peel the garlic from the husk, cut it into slices and arrange in jars. Pour the very hot marinade in your pot into the jars equally. Leave about an inch of space on top of the jar, but no more. Food inside should be completely covered with marinade.
Cover the jars with lids and tighten with rings (sterilize beforehand if you are canning. Directions to can are above). Leave on the table until contents in the jars cool completely.
Can properly for longer storage, then keep in dark place. Or if eating within 1 week keep in fridge.
Notes
NO Boil Method
You would combine the same ingredients above. Put lid on jar tight and shake for a bit to dry to dilute some of the crystals. Add sliced banana peppers making sure they are submerged into the liquid. Seal shut the lid and store in the fridge for 48 hours and then enjoy.