Your spouse has to be approved before a letter for your biometrics is sent. It seems in your case that a letter was sent before your spouse was approved. If she never received the letter, she can send an email to IRCC and let them know and ask them to send it again.It's my wife (Sponsor) who resides in Canada that received 1. Acknowledgement of receipt 2. Sponsor's eligibility approval and also that the application has been sent to visa office accra
I had that issue with my husband first application. IRCC said they sent a letter and I never got it. They didn't want to send me the copy of the letter. I had to go through my MP office to get it.