Basically, if your daughter is under the age of 22 years and is not married or living common-law, she is defined as your dependent by Immigration Canada and you HAVE to include her on your application for permanent status. You would designate her as a non-accompanying dependent - as PMM mentioned - if she does not want to immigrate. But she must still undergo an immigration medical examination and (because she is over the age of 18) submit criminal clearances. Now, from personal experience, I will say that an adult-child "dependent" can sometimes be a minefield - and you need to know this going in. If your daughter has had any arrests since turning age 18, for any reason, she is inadmissible to Canada and you need to read the rest of this reply.
Pursuant to paragraph 42(a) of the Immigration & Refugee Protection Act, if you are applying for permanent status and one of the family members that you are required to include in your application is inadmissible to Canada, and you include that family member as an "accompanying" family member, their inadmissibility makes you inadmissible also. If you designate them as "non-accompanying", you are supposed to be exempted from their inadmissibility making you inadmissible . . . UNLESS (with a dependent) you have custody of the "child" you have designated as non-accompanying (not likely for someone who is 20), or you are "legally empowered to act on (their) behalf". In the absence of both of these conditions, even if an overaged dependent is inadmissible, their inadmissibility is not supposed to make you (the principle applicant) inadmissible. Unfortunately, it seems this is not readily understood by some assessing officers. This is the exact situation I found myself in - no custody, no "legal empowerment" of a non-accompanying 19 yr old son who was inadmissible because of an arrest, and the officer assessing my application still found me inadmissible to Canada because of him.
So - IF this is a possible issue, it's better to have the inadmissible dependent sign and get notarized a statement saying that they have no intention of immigrating to Canada and, as such, refuse to undergo examination. You still have to list them in the application forms, but you submit the notarized statement with the application and they don't cooperate with either the medical or the criminal examinations. CIC won't like it - at all - but they cannot force an overage dependent to be examined. The end result will be that the dependent is forever banned from being sponsored as a member of the family class - but if they really have no intention of ever immigrating to Canada anyway, it won't matter.