“… Holiday wreaths will be placed on the grave during the ceremony…

As a community service, the Postal Service offers pictorial postmarks to commemorate local events celebrated in communities throughout the nation. Usually, people attending these local events may obtain the postmark in person at the temporary Post Office established there. However, there will be no temporary Post Office at this event. COVID-19 restrictions have forced the ceremony to be closed to the public and only those volunteers placing the wreaths may attend. The only way to obtain the special cancel will be by mail order request. Requests must be mailed and postmarked no later than 30 days following the pictorial postmark date.

Collectors wishing to obtain the postmark must affix stamps equal to the First-Class rate to an envelope, address the envelope to themselves or others, insert a card of postcard thickness (or folded paper) in envelopes for sturdiness, and tuck in or seal the flap. Place the envelope or postcard in a larger envelope and address it to the address listed for the cancel. This works but the cover will be returned “unprotected” and will usually receive ugly over cancels and bar codes during its trip through the mail stream. I always use the instructions in the next few paragraphs.

Collectors may also send stamped envelopes, addresses or unaddressed, for postmark as long as they supply a larger self-addressed envelope with adequate postage for their return. After applying the pictorial postmark, the Postal Service returns the items inside the addressed protective cover. This is the only way to obtain the unaddressed covers usually preferred by collectors. This also helps keep your collectable covers clean and undamaged.

Furthermore, he goes onto share his preferences for envelope sizes for requesting.

I use a number #6 ¾ envelope for the collectable cover, a number #9 for the return envelope and a number #10 for the request envelope. The #6 ¾ is the common FDC size, the #9 is the common business return mail size and the #10 is the common business mail size. They all fit inside each other and all the mailing can be done without having to fold any of the envelopes. If you do not have a #9 handy, just fold a #10 and use it for the return envelope.

Also noteworthy, he gives an example of what to write with your cover letter:

I also include a cover letter with my request:
“Please service with the December 19, 2020 Wreaths Across America Station special pictorial cancel. A postage paid return envelope is provided for the return on the cover(s). Thank you for help,”

If mailing multiple covers in one request be sure to apply sufficient extra postage to the request and return envelopes if needed.

And here he provides details on free and limit size before running into a minimal charge per cover:

Cancels are free up to 50 covers per request. There is a charge of 5¢ per cover for any over 50. Example: A bulk order of 100 covers cost $2.50 (50 free plus 5¢ X 50). Check to “Postmaster”. 

Lastly, we have the snail mail address for sending your request:

“Address your request to:

Wreaths Across America Cancel Attn: Lori Tucker
Postmaster
152 N Front Street
Wilmington NC 28401-9998