The noun 'furniture' is an uncountable noun, a type of aggregate noun, a word representing an indefinite number of elements or parts.
To make the noun furniture possessive, you would add apostrophe + S, as below:
The furniture's slipcovers came in the mail today.
The possessive form for the plural noun babies is babies'.Example: The babies' furniture department is on the second floor.
Singular possessive: secretary's Plural: secretaries Plural possessive: secretaries'
The plural is relatives. The plural possessive is relatives'.
The plural is lads. The plural possessive is lads'.
The plural form is echoes. The plural possessive is echoes'.
The plural form is suffixes. The plural possessive is suffixes'.
The plural form is Mexicans. The plural possessive is Mexicans'.
The plural form is stepsisters. The plural possessive is stepsisters'.
The plural form is inches. The plural possessive is inches'.
The plural possessive of "Father" is, "Fathers"
The plural possessive of bandit is bandits'.
Studies' is the plural possessive of study.