At some point prior to surgery your doctor should be ordering lab work that will pick up any current deficiencies that you might have. Once the results are in they should tell you how much of what type of supplements you need along with a multivitamin. Following surgery your multivitamin should have 200% of the daily recommended values. So if you are taking a multivitamin that only has 100%, then your doctor will probably tell you to take 2 following surgery. OR you can go with Bariatric multivitamins which probably already are 200% (you'll need to check the label)
Remember after surgery you won't be able to handle swallowing big pills. That's where the Bariatric vitamins come in handy because they have chewables, soft chews, liquid and even small capsules that are easy to swallow. There are even vitamin patches but I don't believe they cover all the vitamins you will need.
I personally use Celebrate Vitamins but you can also check out Bariatric Fusion, Unjury and Bariatric Advantage. They are not cheap but I've decided to go with them for the first year anyway. After that I might switch to something less pricey. If you have a Trader Joe's near you, that is also a good place for vitamins.