The most common and most likely answer to this crossword clue is the 9 letter word KEYSTROKE
I've seen this crossword clue in The Times
K
E
Y
S
T
R
O
K
E
More clues leading to the result KEYSTROKE
Buddy explains!

The straight part
We know that "Press producing letter, maybe" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case press producing letter, maybe = keystroke.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 KEYSTROKE mean?
KEYSTROKE noun- The act of pressing an input key; a keypress on a computer keyboard or a typewriter, or a similar input device.
- To enter (data etc.) by pressing keys on a keyboard.