Once you’ve identified any problem apps, there are a few options available to deal with them.
Android cautions you to be careful when switching controls with the apps and services it’s running in the background, as halting processes suddenly could cause crashes or malfunctions. If you don’t know what something is, just type the name into Google and find out. You are looking for a third-party app that you installed or some bloatware that you don’t use that seems to be running in the background a lot more than it should. There are many system processes and Google services that you don’t want to mess with.
These controls let you look for apps that are suspiciously busy, even though you don’t use them much. The percentage next to each one tells you how often it’s running and you can tap on it to see its RAM usage.