If you get married before you land, you have to inform IRCC, and you have to add your spouse to the application (whether accompanying or non-accompanying).
Your spouse will be asked to submit a medical, and PCC. This will add 3-4 months to the process, but if you just got your ITA, and are getting married soon, you can add them quickly and it won't take that much time.
If you wish, you can land first and then get married. You won't need to inform IRCC if you land first, become a PR, and then get married.
However, this will mean that you'll have to be separated from your spouse for about a year while you sponsor them through a family sponsorship. If you only just got your ITA, it makes more sense to add your spouse to the application now, so that you can both come to Canada together.