Your child is growing in leaps and bounds, and has now learnt to consume food on their own. This is the perfect phase when you can channelize their actions into learning good habits, one of which is the vital habit of cleanliness.
What you need to know
When the child is 3 years old they have developed the sensibility to understand something that is being taught to them. Be patient with the kid and make them learn about personal hygiene and cleanliness. It is very important to teach the little one about keeping themselves and their surroundings clean.
What you need to do
You can start off with basic steps such as throwing waste paper, wrappers and other disposable stuff into the dustbin. Demonstrate it to the child so that they can form a proper understanding about this habit. Activities such as washing hands before and after every meal, drying wet hands with their personal towel and brushing their teeth twice a day are a few important tasks that must be taught to the child in these initial years.
If the kid is adamant, then figure out fun ways to make them learn lessons on health and hygiene.