Once in recept of Universal Credit you must report any change in circumstance that occurs via your online account. For example, if your partner moves into your household.
If you receive Council Tax Support you should also notify the Council of this change.
If you take up paid work your Universal Credit entitlement will be adjusted as your earned income changes. This means your Universal Credit payment will not stop all at once, but gradually reduce as your earnings increase.
Once you secure a high enough income, your Universal Credit claim will close.
Any future change in circumstance that requires you to re-claim Universal Credit will in most cases require you to re-apply and make a new application.