When will my wife be able to apply for spousal benefits? Or can she begin receiving them immediately?
I'd need much more information to be able to give you a specific answer to your question. What I can tell you is that your wife would have to be at least age 62 to qualify for spousal benefits, unless she has an eligible child in her care who qualifies for child's benefits and who is either under age 16 or disabled. And, you would have to be drawing your Social Security retirement or disability benefits in order for your wife to potentially be paid spousal benefits.
Furthermore, unless your wife was born prior to January 2 1954 she could only qualify for spousal benefits if 50% of your primary insurance amount (PIA) is higher than her own PIA. That's because people born after January 1 1954 are deemed to be filing for both their own Social Security retirement benefits as well as spousal benefits whenever they file for either benefit. And, they can only be paid essentially the higher of those two benefit rates. A person's PIA, by the way, is equal to their Social Security retirement benefit rate if they start drawing at full retirement age (FRA).
Additional rules for qualifying for spousal benefits can be found in the following section of Social Security's handbook: https://www.ssa.gov/OP_Home/handbook/handbook.03/handbook-0305.html. You and your wife may want to consider using our software (https://maximizemysocialsecurity.com/purchase) to fully explore and compare your options so that you can determine the best strategy for maximizing your benefits.