veterans
The VA website just shows it as Veterans Day. There is no apostrophe used. The word "Veteran" is used in its plural form, not in any possessive form.
Actually, neither is correct! The US government has stated that the official name of the holiday is Veterans Day, without any apostrophe. The word "Veteran" is used in its plural form, not in any possessive form.
The correct spelling is just as you have used it in your question, Veterans Day. No apostrophe is used because it is the plural form of the word "Veteran" not any possessive form.
There is no plural form. Do and Do not are verbs
The plural form of him, her, or it is them. (objective pronouns)
Bridges is the plural form of bridge.
The plural form of "was" is "were."
The plural form of "I" is "we."
The plural form of "is" is "are."
The plural form of mouth is mouths. The plural form of month is months. The Mounth is a range of hills in Scotland and does not have a plural form.
"Groceries" is the plural form of "grocery."
"Beliefs" does not have a plural form, as it is already plural. Beliefs is the plural form of belief.