Does the term heirs and assigns in a deed mean it is a joint tenancy deed or a common tenancy deed?

Neither, those are ancient common law simply terms of art that mean the interest being conveyed to the grantee is a fee interest and that the grantee will be able to sell the property while living or it will go to her heirs upon her death.

A joint tenancy must be created by certain language in the deed. In many jurisdictions "as joint tenants" is sufficient. In others you must recite the entire phrase "as joint tenants with right of survivorship". If no tenancy is specified the tenancy usually defaults to a tenancy in common except in those states where a conveyance to a legally married couple automatically creates a joint tenancy with the right of survivorship.

Neither, those are ancient common law simply terms of art that mean the interest being conveyed to the grantee is a fee interest and that the grantee will be able to sell the property while living or it will go to her heirs upon her death.

A joint tenancy must be created by certain language in the deed. In many jurisdictions "as joint tenants" is sufficient. In others you must recite the entire phrase "as joint tenants with right of survivorship". If no tenancy is specified the tenancy usually defaults to a tenancy in common except in those states where a conveyance to a legally married couple automatically creates a joint tenancy with the right of survivorship.

Neither, those are ancient common law simply terms of art that mean the interest being conveyed to the grantee is a fee interest and that the grantee will be able to sell the property while living or it will go to her heirs upon her death.

A joint tenancy must be created by certain language in the deed. In many jurisdictions "as joint tenants" is sufficient. In others you must recite the entire phrase "as joint tenants with right of survivorship". If no tenancy is specified the tenancy usually defaults to a tenancy in common except in those states where a conveyance to a legally married couple automatically creates a joint tenancy with the right of survivorship.

Neither, those are ancient common law simply terms of art that mean the interest being conveyed to the grantee is a fee interest and that the grantee will be able to sell the property while living or it will go to her heirs upon her death.

A joint tenancy must be created by certain language in the deed. In many jurisdictions "as joint tenants" is sufficient. In others you must recite the entire phrase "as joint tenants with right of survivorship". If no tenancy is specified the tenancy usually defaults to a tenancy in common except in those states where a conveyance to a legally married couple automatically creates a joint tenancy with the right of survivorship.

Neither, those are ancient common law simply terms of art that mean the interest being conveyed to the grantee is a fee interest and that the grantee will be able to sell the property while living or it will go to her heirs upon her death.

A joint tenancy must be created by certain language in the deed. In many jurisdictions "as joint tenants" is sufficient. In others you must recite the entire phrase "as joint tenants with right of survivorship". If no tenancy is specified the tenancy usually defaults to a tenancy in common except in those states where a conveyance to a legally married couple automatically creates a joint tenancy with the right of survivorship.