Deleting your videos will not necessarily remove the copyright strike(s) you received. There are two ways to appeal the strike and possibly get it removed.
You will need to sign into the YouTube account that received the copyright strike and go to My Claims in order to retract the claim. If your channel has been terminated, you can submit your retraction to YouTube’s copyright email following the instructions here.
If the company that issued your copyright strike decides to retract their copyright claim, your channel will be back in good standing but that is not guaranteed. This article offers a lot of great advice about how to avoid getting a copyright strike in the future.