As your children go from preschool to school age, their urge to 'help' is going to be stronger than ever. They are going to find just about anything you ask them to do exciting. Enjoy this while it lasts, as it won't last much longer. They want to help, so give them something to do. Even after they stop wanting to help, they should be doing chores to contribute to the well being of the family. There are some jobs for kids that they can do easily to get them started. Later on, more complicated chores can then be assigned.
Some early jobs for kids, even kids as young as five, can be simple things that take just a few minutes but that will give them a sense of accomplishment. Anything longer than five minutes will be too much for them. Ask the to assist you with the laundry. They can carry clothes from the washer to the dryer, or the other way around. Just make sure they can handle what you hand them. They can also help you collect dirty clothes or do some simple folding jobs. They can usually start well with wash clothes and other items that just take a few simple folds to complete.
Kids at five, six, and seven can help set the table before a meal and can help clean up when everyone is done eating. They are not too young to learn to clean off their own plate and rinse things off. You may not want them to put things in the dishwasher just yet, but if you think they can handle it, that is something they can do as well. Children of this age can also sweep some floors for jobs for kids, but you may have to watch them carefully and you may have to redo it when they are not looking.
As they age past seven and eight, you can add some more jobs for kids to what you want or expect them to do. They can do a better job with sweeping, and can even learn to mop. Give them small areas so they can be satisfied with a good well done. They can do more with the laundry, and they can also learn to dust some areas of the house. At this age, they can learn some simple cooking skills, but they are still too young to cook on their own. See how they handle what you give them and ideas for new things for them to try will come to you as you see them grow.
Jobs for kids are going to be fun for them, but not forever. Soon enough they are going to be grunting and groaning about doing chores and telling you that they need to get an allowance. Remind them that you do these things without an allowance all the time and they can do the same for the good of the family. However, they can earn an allowance by doing more than you require from them. What those things are can be up to you. Chores won't be fun forever, but they certainly help you out and give them good values for the future.