Keeping in mind there needs to be more context in the question I'll answer this as best as I can.
Starting off people sometimes reward themselves after reaching a goal to increase their productivity and to feel good about what they did.
A reward you could give yourself could be to let yourself eat one of your favorite foods or eat out. For example if you were on a diet this would be your one rewarding break and to make sure you don't break your routine or what you did you could limit your consumption.
- Designate a day where you will do nothing
Another reward could be to choose a day where you can do nothing so if again you were on a diet or trying to loose weight this could be your one chance to rest.
- Buy something for yourself
This reward could be something to help promote your happiness and if you want every time you reach a goal you increase the amount of money you spend on yourself. This doesn't just talk about things you buy at the store this could also
This reward honestly varies from person to person and you could do things like take a relaxing nap, take a bath, do an activity, or take on learning a new skill.