Husband and wife are owners of a triplex property, both are listed on all mortgage/deed documents. If the husband were to pass away would his wife be sole legal owner of property or are her stepchildren (husband's kids from previous marriage) entitled to any portion. Husband and wife have 1 biological daugther as well. No will is in place.

1. What state is this?
2. What is the exact wording of the deed on the owner's line, e.g. Jack and Jill, tenants in common, or joint tenants, etc?

Wording varies by state, as do certain other details, and the wording determines who gets real estate.
But generally 'joint tenancy' means that the surviving owner gets the property in it's entirety.

As noted the wording of the deed matters and ANY question on law needs to include your general locale as laws vary by area.

If the deed specifies right of survivorship, then the other owner gets full ownership in case of death. If the survivorship is not specified, then the other owner's share can be left in a will. If the re is a death without a will, then, depending on local laws of inheritance, the heirs may be entitled to some share of the deceased's share.

It's also possible to have a deed written to a married couple with no additional terminology.
In my state (again, this goes by state) this presumes tenants in common, not joint tenants. A tenant in common does not automatically get ownership as survivor.

'Joint tenants' and 'joint tenants with right of survivorship' on a deed both mean the same thing.

'Joint tenants' and 'joint tenants with right of survivorship' on a deed both mean the same thing.

Actually it depends on the local custom. In some cases the phrase "joint tenants" alone isn't enough. It may need to be qualified by In common or with right of survivorship.

Actually it depends on the local custom. In some cases the phrase "joint tenants" alone isn't enough. It may need to be qualified by In common or with right of survivorship.

Right! I should have said 'in my state.'

...or are her stepchildren (husband's kids from previous marriage) entitled to any portion. ... no will is in place.

No. They would not. A will is necessary to leave the step-children anything.