When working in SOLIDWORKS, you sometimes need to create a mirrored version of a part. Fortunately, there is a feature built in for just this task.
Click on the surface or plane you wish to mirror from and go to "Insert" ➔ "Mirror part". Now you can select which parts of the model you want to mirror.
❗ One important check mark to consider is "Break link to original part".
● If you keep the link (unchecked), the mirrored part will update when the original part is changed.
● If you decide to break the link you get a new part with features that can be updated independently with its own set of features.