The most common and most likely answer to this crossword clue is the 6 letter word SEAMER
S
E
A
M
E
R
More clues leading to the result SEAMER
Buddy explains!

The straight part
We know that "delivery" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case delivery = seamer.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does SEAMER mean?
SEAMER noun- A person who sews seams.
- Part of a sewing machine that creates seams.
- A bowler skilled at making the ball seam.