You can apply electronically. You will get your results 3-5 business days after they receive your fingerprints. It is MUCH faster than sending the application through the mail. You still mail in your fingerprints and they match it to your electronic application. I had the results in my hand about a week after I mailed my fingerprints in.
I’ll be starting my US to Canada app process soon (3 months or less)...are the fingerprints something that can be done in advance to avoid additional wait time? FWIW, I already have FBI clearance through my current employer, would IRCC accept those or do I need to do it all over again?
Yes, you are correct. I just went to the FBI website I posted above and used the eDO option. I printed the card at home on card stock and took it to the crime lab in Kansas City where I live. They charged $16 to make the fingerprint impressions for me. They actually had the correct fingerprint cards there, so I wouldn't even have needed to bring one. Alternatively, you can do the fingerprints yourself. There are tips for how to get good impressions and what they are looking for on that same link, but I wanted to make sure they were done correctly since I've heard stories of people who sent in prints they had taken themselves and had issues with readability and had to re-do them.
It can be done in advance, and you do need to send in the FBI certificate upfront with your spousal application. One caveat is that you don't want to do it too far in advance because they will usually ask for another one if it expires while your application is being processed (usually good for 12 months). I had FBI clearance from my employer as well, but you'll still need to do it again so that you can have the current certificate to send in.
