What is going to failure?
Going to failure in an exercise means doing a certain exercise until you are unable to simply continue, and it can be in the middle.
It is not recommended to overuse this technique as it is very taxing on the CNS (central nervous system).
Are you doing bench press and you've already done 7 reps.
You advance to the 8th repetition but you can't lift any more, the repetition is in the middle and someone has to help you put the bar on the support.
This is going to failure.