〜てください: asking someone to act
Attach ください to the te-form to ask someone to act. Compare requests for an action, requests for an item, and requests not to do something, while considering how direct they sound.
Request a specific action
名前を書いてください。 means 'Please write your name.' Change 書く to 書いて before adding ください. 読む gives 読んでください, and 待つ gives 待ってください.
Include necessary details about what to do and where. ここに名前を書いてください。 specifies where to write the name. A polite ending alone does not remove ambiguity from the request itself.
Items and negative requests
水をください。 means 'Please give me some water,' using noun + をください. 水を飲んでください。 asks the other person to drink water. Although both mention 水, they request different actions.
'Please do not write' is 書かないでください: add でください to the nai-form. It is not formed by simply adding ない to 書いてください. Practice affirmative and negative requests as a pair.
Consider tone and situation
〜てください is also common in instructions and can sound direct in some situations. If you want to ask whether someone could help, another request form such as 書いていただけますか may be suitable.
Choose wording according to the person's role, the burden involved, and whether the procedure is already agreed. Rather than making every sentence longer, make the requested action and reason clear and allow room for a response.
Check: How do you say 'Please do not take photographs here'?
Show the answer and why
ここで写真を撮らないでください。 uses 撮らない, the nai-form of 撮る, followed by でください to request that the action not be performed.