Annotative threads and Threads both can used to create thread

I’m not sure what you mean by “correct” thread, but there are 2 common problems with SolidWorks threads.

1) The actual shape of the thread profile is not correct which is a problem if you 3D print threads. This can be corrected by making a copy of one of the built in thread profiles and adding a radius to the root or tip depending on whether it is an internal or external thread.

2) There is also a problem that not all standard threads are in the lookup table. Again I recommend making a copy of a close thread and adding the thread you would like. The SolidWorks thread profile equation is incomplete so adding a new thread requires the calculation of the thread height or you can correct the equation and make it easier to add threads in the future. The equations can be found here:

https://en.m.wikipedia.org/wiki/ISO_metric_screw_thread

First you make a helix with the thread diameter as the base circle then convert the helix to a 3D sketch. Then you add a plane to the end of the 3D sketch by selecting the 3D sketch and its end point. On the plane you create a dimensionally accurate thread form then make a swept cut using the 3D sketch as the path and the threadform sketch as the profile.