What is correct Mr and Mrs graciously accept or graciously accepts?

If it's a reply to a wedding intivation, one traditionally writes in longhand, with these line breaks (I hope they come thru)

Mr. and Mrs. Jones

accept with pleasure

the kind invitation

of Mr. and Mrs. Smith

To decline an invitation,

Mr. and Mrs. Jones

regret exceedingly

the kind invitation

of Mr. and Mrs. Smith.