I am a Canadian citizen who is living in the USA with my American spouse. If we were to consider moving to Canada, which would be the quickest option to get us both moved there? I did some research, but some things are confusing. Can my spouse just cross the border with me and then apply? Or do we have to apply first and wait until it is approved. I though t I read that as long as it's in processing we can move there, but I am uncertain what that entails. Thank you for anyone who can help!
You can do either, basically, or apply immediately and then move during the process. Depends whether/how important it is for your spouse to begin working immediately - if you apply in advance,he may get the PR quickly enough to begin working right away when he arrives (a permanent resident requires no addl permission to work).
One warning: your spouse can't "move" or be seen to move if he's arriving before he gets PR status. Meaning, he can't show up with all of his stuff and his purpose is to visit. If that happens to change during the process and he's in Canada as a visitor (e.g. he gets the PR status or decides to extend his visit), that's fine. (The border guards can be a bit prickly about people showing up 'moving' without any permission to do so).
If you apply from abroad, you will have to demonstrate your intent to return. That's not necessarily that difficult but will require some prep. I'd download the application package and get acquainted with it, come back with questions. Note the family sponsorship sub-forum here is the most appropriate to your case.