Legal Question in Real Estate Law in California

Either a grant deed or a quitclaim deed would be effective to create a shared ownership, but this is just the tip of the huge iceberg.

As the balance of your post suggests, newlywed couples should do comprehensive financial planning that incudes, perhaps, the nicety of sharing your worldly possessions, but also considers the substantial damage that the various tax collectors can inflict upon the unwary.

In addition, deeds written by novices are prone to costly mistakes, such as errors in description of the property, poor choices in how title will be held, mistakes in the granting clause, and so forth.

If you are making wills and directives and thinking of transferring partial interests in real property, you and your heirs will benefit from professional advice on taxes, family wealth planning, probate avoidance, use of trusts, etc.

What you really need is a comprehensive plan, not a particular instrument.

By the way, co-owners are not "added to the deed." A deed is a one-use instrument. What you mean is "added to title." This is done with a deed, hopefully a deed drawn up as a part of a professionally-prepared long-term plan.

Mr. Whipple is giving you very good advice. I would just add that a quitclaim deed is not appropriate to add a party to title while the grantor retains an interest. That would need to be a grant deed from X to X and Y as (joint tenants, community property, cotenants, or whatever from best fits your needs)