The correct indirect form of the sentence is:

The judge told Jia to stand in the witness box.

The other options are incorrect:

• The judge told Jia you will stand in the witness box. This is incorrect because the tense of the reported speech is in the future tense, but the reporting verb is in the past tense.
• The judge told to Jia stand in the witness box. This is incorrect because we do not use the preposition "to" after the verb "told" when giving a command.
• The judge told Jia you are standing in the witness box. This is incorrect because the reported speech is describing an action that is happening now, not an action that is being commanded.