When address to the staffs of the company, should the "To" line be All staff or All staffs?

also, how can you phrase these sentences better?

We have to cancel this party because we don't have time to organize it this year.

If you are willing to volunteer to help plan the party, you can contact....

If there is more than one staff, you would use To: The Staffs. If there is only one total staff, then it will be To: The Staff.

Question... what party? Xmas? New Years? Be specific.

I would phrase that sentence.
The .... party must be cancelled this year because of a lack of time for organization.

and

If you would enjoy planning helping to plan a party for the staff, please contact ......

When addressing the staff of a company, the correct phrase to use is "To: All staff," not "To: All staffs." Here's why:

The word "staff" is what is known as a collective noun. It refers to a group of people working together as a team, in this case, the employees of a company. Collective nouns are singular in nature, which means they do not typically take a plural form.

Using the plural form "staffs" suggests that you are referring to multiple groups of staff members within the company, rather than addressing the entire collective as one unit. This usage is less common and can be considered non-standard.

To make your communication grammatically correct and clear, stick to the singular collective noun "staff" and address your message as "To: All staff."

If you want to address specific individuals or departments within the staff, you can mention them separately in the body of your message after the salutation.