apostrophe plurals
Whether an apostrophe marks an ordinary plural.
Do not use an apostrophe to make a regular noun plural: forms, memos, the Joneses. An apostrophe plus s may mark the plural of a single letter when the plain s would be unclear: Mind your p’s and q’s. Dot the i’s. For capital letters and numerals, prefer no apostrophe: three As, the 1990s. Do not write CD’s, photo’s, or 1990’s as plurals.
Examples
Use Bring two IDs.
Avoid Bring two ID’s.
Use Cross the t’s.
Avoid The memo’s are on the desk.